Ringraziamo Drs. Erez Eliyahu, Daniel Melamed, Ophry Pini e Doron Rapaport aiuto e commenti durante la creazione di questo protocollo. Questo lavoro è finanziato dalla ISF (codice di autorizzazione 1193-1109).

1. I mitocondri Purificazione Pesare il pellet di cellule. Circa 0,6 g si ottengono da cellule di 100 ml. <ol><li> Crescere 100-150 ml di cellule di lievito di OD 600 = 1-1.5 al 30 ° C su un terreno di crescita non fermentabili, come mezzo di crescita a base-galattosio, per arricchire di mitocondri. </li><li> Centrifugare le cellule a 3.000 xg per 5 minuti a temperatura ambiente e scartare il surnatante. </li><li> Lavare il pellet con acqua bidistillata e centrifugare di nuovo. Scartare il surnatante. </li><li> Risospendere il pellet in 1 ml DTT tampone in 0,5 g di cellule. È importante trattare le cellule con un agente riducente per rompere i legami disolfuro all&#39;interno della parete cellulare, migliorando così idrolisi. </li><li> Incubare le cellule per 10 min a 30 ° C con un leggero scuotimento. Nel frattempo, pesare 6 mg zymolyase per 1 g di cellule e di sospendere in Zymolyase Buffer. </li><li> Centrifugare le cellule a 3.000 xg per 5 min atemperatura t camera e scartare il surnatante. </li><li> Risospendere il pellet in 1 ml di tampone per Zymolyase 0,15 g di cellule. Non vortex. </li><li> Misurare OD 600 di 10 microlitri aliquota di cellule in 990 ml di acqua. </li><li> Aggiungere Zymolyase (passo 1.5) alle cellule di idrolizzare polimeri del glucosio a β-1 ,3-glucano collegamenti e generare sferoplasti. Da questo punto, sferoplasti devono essere conservati in una soluzione isotonica per evitare lisi. </li><li> Incubare le cellule per 15 min a 30 ° C (per attività ottimale di zymolyase) agitando delicatamente. Per verificare idrolisi della parete cellulare e sferoplasti generazione, mescolare 10 ml di cellule con 990 ml di acqua. Sferoplasti sono attesi per lisare dovuto la differenza osmotica, e la OD 600 devono essere almeno 10 volte inferiore al valore determinato nella fase 1.9. In caso contrario, continuare l&#39;incubazione con zymolyase per altri 15 min. </li><li> Cellule centrifugare a 3000 xg per 5 minuti a temperatura ambiente. Dis cautelacarta il surnatante, il pellet come potrebbe essere instabile. </li><li> Lavare sferoplasti con Zymolyase Buffer e scartare il surnatante. </li><li> Risospendere sferoplasti con 100 ml di media Recovery. Trasferire sferoplasti ad una beuta e incubare per 1 ora a 30 ° C con agitazione. Questo passaggio di recupero è necessario in quanto durante la definizione Zymolyase trattamento viene arrestato e localizzazione mRNA viene interrotto (Figura 1B). </li><li> Aggiungere 0,1 mg / ml CHX e trasferimento sferoplasti preraffreddato ad un tubo da 50 ml. CHX aggiunta è importante per congelare l&#39;associazione ribosomi &#39;con mRNA. Così, ribosomi-dipendenti mRNA associazione con i mitocondri è mantenuta. </li><li> Sferoplasti centrifugare a 3000 xg per 5 minuti a 4 ° C e scartare il surnatante. </li><li> Lavare due volte con il freddo mannitolo Buffer. </li><li> Risospendere sferoplasti con 4 ml di freddo mannitolo buffer e trasferirli in un omogeneizzatore Dounce di 15 ml, dotato di chiusura ermeticapestello. Rompere delicatamente sferoplasti con 15 colpi e trasferire il lisato in una provetta da 13 ml. </li><li> Centrifugare il lisato a 1.500 xg per 6 minuti a 4 ° C a pellet nuclei e cellule intatte. </li><li> Trasferire con attenzione il surnatante in una nuova provetta. Mettere da parte 1 ml (25%) del campione come un campione non frazionata (campione &quot;Totale&quot;). Trasferimento 50 ml di questo campione a un nuovo tubo e aggiungere 15 ml di 4X LSB per l&#39;analisi western blot. RNA precipitato dal resto del campione &quot;Totale&quot; (Vedi protocollo 3, RNA precipitazione). </li><li> Centrifugare il surnatante a 10.000 xg per 10 min a 4 ° C per far sedimentare i mitocondri. </li><li> Trasferire il surnatante (~ 3 ml) in una nuova provetta e mantenere in ghiaccio. Questa è la frazione &quot;citosolico&quot;. Trasferimento 50 ml di questo campione a un nuovo tubo e aggiungere 15 ml di 4x LSB per l&#39;analisi western blot. RNA precipitato dal resto del campione &quot;citosolico&quot; (Vedi Protocol 3, RNA precipitazione). </li><li> Lavare il pellet con 3 ml Mannitolo Buffer e centrifugare nuovamente a 10.000 xg per 10 min a 4 ° C. </li><li> Risospendere il pellet con 3 ml di mannitolo Buffer. Questo esempio contiene i mitocondri, e indicato come frazione &quot;mitocondri&quot;. Trasferimento 50 ml di questo campione a un nuovo tubo e aggiungere 15 ml di 4x LSB per l&#39;analisi western blot. </li></ol> 2. RNA Estrazione <ol><li> Aggiungere a ciascun campione un volume di 8 M guanidina-HCl e due volumi di etanolo al 100%. Vortex e incubare per almeno 2 ore a -20 ° C. </li><li> Centrifugare i campioni a 10.000 xg per 20 min a 4 ° C. Scartare il surnatante. Fare attenzione a come il pellet potrebbe essere instabile. </li><li> Lavare il pellet con il 70% EtOH. </li><li> Risospendere il pellet con 400 ml di acqua priva di RNasi e trasferire il campione in una nuova provetta Eppendorf. </li><li> Precipitare nuovamente l&#39;RNA aggiungendo 0,1 volume di 3 M acetato di sodioe pH 5.2 e due volumi di 100% EtOH. Vortex e incubare per almeno 2 ore a -20 ° C. </li><li> Centrifugare i campioni a 20.000 xg per 20 min a 4 ° C. Eliminare il surnatante e lavare con il 70% EtOH. </li><li> Far asciugare il pellet e risospendere con acqua RNase-free. Conservare i campioni di RNA a -80 ° C. I campioni possono essere usate per analisi Northern 19 o analisi microarray 18 (Vedi protocollo 3). </li></ol> 3. Preparazione del RNA per l&#39;analisi Microarray <ol><li> Risospendere il mRNA dal punto 2.2 con 650 ml di acqua RNase-free. </li><li> Per rimuovere eventuali residui di DNA o di proteine, aggiungere un volume uguale (650 ml) di acido fenolo: cloroformio (5:1, pH 4.7) e agitare vigorosamente. Centrifugare alla massima velocità per 2 min. </li><li> Trasferire 500 ml della fase superiore (fase acquosa) in una nuova provetta. Evitare di prendere l&#39;interfase, in quanto contiene il DNA. Fate anche attenzione di prendere fenolo, che può inibire la reazione di trascrizione inversa. &lt;/ Li&gt; <li> Il campione di RNA contiene una notevole quantità di eparina, che è un potente inibitore della trascrittasi inversa. Così, per RT-PCR o etichettatura microarray deve essere rimosso. Rimuovere eparina da LiCl precipitazioni: aggiungere LiCl ad una concentrazione finale di 2 M e incubare i campioni per tutta la notte a -20 ° C. </li><li> Scongelare i campioni a 4 ° C e centrifugare a 20.000 xg per 20 min a 4 ° C. </li><li> Scartare con cura il surnatante e lavare il pellet con l&#39;80% di etanolo. Centrifuga di nuovo come descritto nel passaggio 3.5. </li><li> Eliminare il surnatante, aria secca e risospendere il pellet in 150 ml di acqua RNase-free. </li><li> Per rimuovere qualsiasi residuo LiCl, precipitare di nuovo con 0,1 volumi di acetato di sodio 3 M pH 5,3 e 3 volumi di etanolo al 100%. Incubare a -20 ° C per almeno 2 ore. </li><li> Centrifugare alla massima velocità per 20 min a 4 ° C. Lavare accuratamente il pellet trasparente con 80% etanolo e asciugare all&#39;aria. </li><li> Risospendere ilpellet con acqua RNase-free 25 ml e conservare i campioni a -80 ° C. </li><li> Seguire la procedura per l&#39;etichettatura RNA e ibridazione descritto in 18,20. </li></ol>

<ol>
	<li>Holt, C. E., Bullock, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Subcellular+mRNA+localization+in+animal+cells+and+why+it+matters.">Subcellular mRNA localization in animal cells and why it matters.</a> Science. 326, 1212-1216 (2009).</li><li>Donnelly, C. J., Fainzilber, M., Twiss, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Subcellular+communication+through+RNA+transport+and+localized+protein+synthesis.">Subcellular communication through RNA transport and localized protein synthesis.</a> Traffic. 11, 1498-1505 (2010).</li><li>Kellems, R. E., Allison, V. F., Butow, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cytoplasmic+type+80+S+ribosomes+associated+with+yeast+mitochondria.+II.+Evidence+for+the+association+of+cytoplasmic+ribosomes+with+the+outer+mitochondrial+membrane+in+situ.">Cytoplasmic type 80 S ribosomes associated with yeast mitochondria. II. Evidence for the association of cytoplasmic ribosomes with the outer mitochondrial membrane in situ.</a> J. Biol. Chem. 249, 3297-3303 (1974).</li><li>Kellems, R. E., Butow, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cytoplasmic+type+80+S+ribosomes+associated+with+yeast+mitochondria.+3.+Changes+in+the+amount+of+bound+ribosomes+in+response+to+changes+in+metabolic+state.">Cytoplasmic type 80 S ribosomes associated with yeast mitochondria. 3. Changes in the amount of bound ribosomes in response to changes in metabolic state.</a> J. Biol. Chem. 249, 3304-3310 (1974).</li><li>Suissa, M., Schatz, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Import+of+proteins+into+mitochondria.+Translatable+mRNAs+for+imported+mitochondrial+proteins+are+present+in+free+as+well+as+mitochondria-bound+cytoplasmic+polysomes.">Import of proteins into mitochondria. Translatable mRNAs for imported mitochondrial proteins are present in free as well as mitochondria-bound cytoplasmic polysomes.</a> J. Biol. Chem. 257, 13048-13055 (1982).</li><li>Fujiki, M., Verner, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coupling+of+cytosolic+protein+synthesis+and+mitochondrial+protein+import+in+yeast.+Evidence+for+cotranslational+import+in+vivo.">Coupling of cytosolic protein synthesis and mitochondrial protein import in yeast. Evidence for cotranslational import in vivo.</a> J. Biol. Chem. 268, 1914-1920 (1993).</li><li>Yogev, O., Karniely, S., Pines, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Translation-coupled+translocation+of+yeast+fumarase+into+mitochondria+in+vivo.">Translation-coupled translocation of yeast fumarase into mitochondria in vivo.</a> J. Biol. Chem. 282, 29222-29229 (2007).</li><li>Eliyahu, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tom20+mediates+localization+of+mRNAs+to+mitochondria+in+a+translation-dependent+manner.">Tom20 mediates localization of mRNAs to mitochondria in a translation-dependent manner.</a> Mol. Cell. Biol. 30, 284-294 (2010).</li><li>Garcia, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitochondria-associated+yeast+mRNAs+and+the+biogenesis+of+molecular+complexes.">Mitochondria-associated yeast mRNAs and the biogenesis of molecular complexes.</a> Mol. Cell. Biol. 18, 362-368 (2007).</li><li>Marc, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genome-wide+analysis+of+mRNAs+targeted+to+yeast+mitochondria.">Genome-wide analysis of mRNAs targeted to yeast mitochondria.</a> EMBO Rep. 3, 159-164 (2002).</li><li>Gadir, N., Haim-Vilmovsky, L., Kraut-Cohen, J., Gerst, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Localization+of+mRNAs+coding+for+mitochondrial+proteins+in+the+yeast+Saccharomyces+cerevisiae.">Localization of mRNAs coding for mitochondrial proteins in the yeast Saccharomyces cerevisiae.</a> RNA. 17, 1551-1565 (2011).</li><li>Margeot, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+Saccharomyces+cerevisiae,+ATP2+mRNA+sorting+to+the+vicinity+of+mitochondria+is+essential+for+respiratory+function.">In Saccharomyces cerevisiae, ATP2 mRNA sorting to the vicinity of mitochondria is essential for respiratory function.</a> J EMBO. 21, 6893-6904 (2002).</li><li>Saint-Georges, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Yeast+mitochondrial+biogenesis:+a+role+for+the+PUF+RNA-binding+protein+Puf3p+in+mRNA+localization.">Yeast mitochondrial biogenesis: a role for the PUF RNA-binding protein Puf3p in mRNA localization.</a> PloS one. 3, (2008).</li><li>Quenault, T., Lithgow, T., Traven, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PUF+proteins:+repression,+activation+and+mRNA+localization.">PUF proteins: repression, activation and mRNA localization.</a> Trends Cell Biol. 21, 104-112 (2011).</li><li>Garcia, M., Delaveau, T., Goussard, S., Jacq, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitochondrial+presequence+and+open+reading+frame+mediate+asymmetric+localization+of+messenger+RNA.">Mitochondrial presequence and open reading frame mediate asymmetric localization of messenger RNA.</a> EMBO Rep. 11, 285-291 (2010).</li><li>Eliyahu, E., Lesnik, C., Arava, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+protein+chaperone+Ssa1+affects+mRNA+localization+to+the+mitochondria.">The protein chaperone Ssa1 affects mRNA localization to the mitochondria.</a> FEBS Lett. 586, 64-69 (2012).</li><li>Ahmed, A. U., Fisher, P. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Import+of+nuclear-encoded+mitochondrial+proteins:+a+cotranslational+perspective.">Import of nuclear-encoded mitochondrial proteins: a cotranslational perspective.</a> Int. Rev. Cell Biol. 273, 49-68 (2009).</li><li>Eliyahu, E., Melamed, D., Arava, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genome-wide+analysis+of+RNA+extracted+from+isolated+mitochondria.">Genome-wide analysis of RNA extracted from isolated mitochondria.</a> Methods Mol. Biol. 714, 287-299 (2011).</li><li>Eldad, N., Yosefzon, Y., Arava, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+and+characterization+of+extensive+intra-molecular+associations+between+3'-UTRs+and+their+ORFs.">Identification and characterization of extensive intra-molecular associations between 3'-UTRs and their ORFs.</a> Nucleic Acids RES. 36, 6728-6738 (2008).</li><li>Melamed, D., Arava, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genome-wide+analysis+of+mRNA+polysomal+profiles+with+spotted+DNA+microarrays.">Genome-wide analysis of mRNA polysomal profiles with spotted DNA microarrays.</a> Methods Enzymol. 431, 177-201 (2007).</li><li>Margeot, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Why+are+many+mRNAs+translated+to+the+vicinity+of+mitochondria:+a+role+in+protein+complex+assembly.">Why are many mRNAs translated to the vicinity of mitochondria: a role in protein complex assembly.</a> Gene. 354, 64-71 (2005).</li><li>Mathieu, L., Marsy, S., Saint-Georges, Y., Jacq, C., Dujardin, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+transcriptome+screen+in+yeast+identifies+a+novel+assembly+factor+for+the+mitochondrial+complex+III.">A transcriptome screen in yeast identifies a novel assembly factor for the mitochondrial complex III.</a> Mitochondrion. 11, 391-396 (2011).</li><li>Hocine, S., Raymond, P., Zenklusen, D., Chao, J. A., Singer, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-molecule+analysis+of+gene+expression+using+two-color+RNA+labeling+in+live+yeast.">Single-molecule analysis of gene expression using two-color RNA labeling in live yeast.</a> Nat. Methods. 10, 119-121 (2013).</li><li>Park, H. Y., Buxbaum, A. R., Singer, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single+mRNA+tracking+in+live+cells.">Single mRNA tracking in live cells.</a> Methods Enzymol. 472, 387-406 (2010).</li><li>Thompson, M. A., Casolari, J. M., Badieirostami, M., Brown, P. O., Moerner, W. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+tracking+of+single+mRNA+particles+in+Saccharomyces+cerevisiae+using+a+double-helix+point+spread+function.">Three-dimensional tracking of single mRNA particles in Saccharomyces cerevisiae using a double-helix point spread function.</a> Proc. Natl. Acad. Sci. U.S.A. 107, 17864-17871 (2010).</li><li>Tyagi, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+intracellular+RNA+distribution+and+dynamics+in+living+cells.">Imaging intracellular RNA distribution and dynamics in living cells.</a> Nat. Methods. 6, 331-338 (2009).</li><li>Garcia, M., Darzacq, X., Devaux, F., Singer, R. H., Jacq, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Yeast+mitochondrial+transcriptomics.">Yeast mitochondrial transcriptomics.</a> Methods Mol. Biol. 372, 505-528 (2007).</li><li>Reinders, J., Sickmann, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proteomics+of+yeast+mitochondria.">Proteomics of yeast mitochondria.</a> Methods Mol. Biol. 372, 543-557 (2007).</li><li>Meisinger, C., Sommer, T., Pfanner, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+of+Saccharomcyes+cerevisiae+mitochondria+devoid+of+microsomal+and+cytosolic+contaminations.">Purification of Saccharomcyes cerevisiae mitochondria devoid of microsomal and cytosolic contaminations.</a> Anal. Biochem. 287, 339-342 (2000).</li><li>Glick, B. S., Pon, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+highly+purified+mitochondria+from+Saccharomyces+cerevisiae.">Isolation of highly purified mitochondria from Saccharomyces cerevisiae.</a> Methods Enzymol. 260, 213-223 (1995).</li><li>Boldogh, I. R., Pon, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+and+subfractionation+of+mitochondria+from+the+yeast+Saccharomyces+cerevisiae.">Purification and subfractionation of mitochondria from the yeast Saccharomyces cerevisiae.</a> Methods Cell Biol. 80, 45-64 (2007).</li><li>Rieder, S. E., Emr, S. D., Bonifacino, J. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Isolation of subcellular fractions from the yeast Saccharomyces cerevisiae. Current protocols in cell biology / editorial board. 8, (2001).</li><li>Diekert, K., de Kroon, A. I., Kispal, G., Lill, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+subfractionation+of+mitochondria+from+the+yeast+Saccharomyces+cerevisiae.">Isolation and subfractionation of mitochondria from the yeast Saccharomyces cerevisiae.</a> Methods Cell Biol. 65, 37-51 (2001).</li></ol>

Gli autori dichiarano interessi finanziari concorrenti.

I progressi tecnologici nella diagnostica per immagini hanno dato strumenti ad alta risoluzione per studiare la localizzazione mRNA. Oggi, si può misurare il movimento di una singola molecola di mRNA a scala msec 23-26. Tuttavia, gli approcci tradizionali biochimici, come quello sopra descritto, sono anche informativo e sono preferibili in alcuni casi. Isolamento Biochemical permette la purificazione di un grande repertorio di mRNA e proteine, ed è quindi preferibile per studi genoma di ampiezza. In un sing...

Le cellule eucariotiche sono organizzate in compartimenti distinti aventi funzioni specifiche. Per realizzare la sua funzione, ciascun compartimento contiene un insieme unico di proteine ​​che sono essenziali per la sua attività. Un possibile meccanismo attraverso il quale queste proteine ​​si avvicinano loro scompartimento è di 1,2 traduzione localizzata. In questo processo, la proteina è sintetizzata a destinazione ribosomi e mRNA che si trovano lì. Tra i probabili vantaggi di una versione localizzata sono aumentati efficienza della proteina targeting, ridotto bisogno di accompagnatori di proteine, e consentendo meccanismi di regolazione site-specific. Inoltre, mRNA e ribosomi in lingua possono essere un serbatoio appartata di macchinari traduzione in casi di stress cellulare, quando la traduzione generale è inibita. I mitocondri è diventato negli ultimi anni un modello centrale per lo studio di traduzione localizzata. La maggior parte delle proteine ​​mitocondri sono codificate nel nucleo, tradotto nel citosol,e importati nel organello. Varie evidenze indicano che molte di queste proteine ​​sono prodotte attraverso un processo di traduzione locale. Inizialmente, gli studi di microscopia elettronica e di frazionamento biochimico rilevati ribosomi associati con i mitocondri 3-5. Questi studi dove poi corroborati in vivo dal lavoro su specifici mRNA, che sono stati trovati ad essere importati solo in modo 6,7 cotranslational. Studi genoma di ampiezza di mRNA associazione con mitocondri rivelato che una frazione significativa di mRNA sono localizzate ai mitocondri vicinanze 8-10. Alcuni di questi mRNA sono stati ulteriormente caratterizzati dal vivo fluorescenza metodi, come il pesce o MTAG 9,11. Un&#39;interpretazione straight-forward di questa associazione è che questi mRNA servono come modelli per la traduzione localizzata. I meccanismi con cui questi mRNA avvicinano i mitocondri sono sconosciute. Domini non codificanti (più significantly 3 &#39;UTR) hanno dimostrato di essere coinvolti in mRNA associazione ai mitocondri 12. Questi domini sono suscettibili di servire come un sito di legame di RNA-binding proteins che mediano il loro trasporto. Gli studi in lievito hanno rivelato che un membro della famiglia PUM delle proteine ​​(Puf3) supporta mRNA associazione con mitocondri 8,13. Un ruolo plausibile per Puf3, che si basa su funzioni di altri membri della famiglia, è quello di inibire traduzione mentre il mRNA è rotta 14. Così, mRNA possono essere trasportati in uno stato nontranslated, da RNA proteine ​​leganti che interagiscono con le regioni non codificanti. In alternativa, un grande corpo di lavoro suggerisce che il trasporto avviene mentre la proteina viene sintetizzata. In particolare, gli inibitori di traduzione sono stati mostrati ad incidere mRNA associazione 8,13. Inoltre, caratteristiche tradotte come l&#39;AUG, sequenza di targeting mitocondriale (MTS) o regioni ORF sono stati indicati come ausilio nella localizzazione 8,11,15. Hsp70-famiglia di proteine ​​chaperone e proteina recettore sulla membrana esterna mitocondriale anche stati mostrati per sostenere associazione mRNA, ulteriormente implicando che funzioni codificate proteine ​​sono importanti per la localizzazione mRNA 16. Questo è coerente con un modello in cui la proteina-ribosoma emergente serve come elemento di riconoscimento per il targeting complesso mRNA-ribosoma-proteina ai mitocondri 17. Traduzione localizzata vicino mitocondri è stato studiato con vari metodi, tra cui la microscopia elettronica (per visualizzare ribosomi) 3, FISH 9, RNA verde (per rilevare specifici mRNA) 11, e frazionamento biochimico (a rilevare sia RNA e ribosomi) 10,18. Mentre i metodi precedenti rilevano localizzazione in vivo e può permettere la visualizzazione delle dinamiche di trasporto, quest&#39;ultimo permette la rilevazione di molti mRNA differenti in un singolo esperimento. Inoltre, per i domini biochimica codifica frazionamento o non codificanti non hanno bisogno di essere alfiltranti quindi i loro ruoli specifici può essere valutato. Frazionamento biochimico è stato utilizzato con successo per molti anni, per l&#39;isolamento di molti compartimenti cellulari diversi. I suoi principi e le limitazioni sono ben stabiliti, e si può facilmente modificare i protocolli esistenti per scopi diversi. La strumentazione necessaria è standard in molti laboratori, quindi di solito è il primo metodo di scelta per studiare la localizzazione intracellulare. Descriviamo un protocollo che è stato ottimizzato per l&#39;isolamento di mRNA mentre ribosomi sono associati con i mitocondri. Questo protocollo è quindi ottimale per studiare fattori coinvolti in una versione localizzata vicino mitocondri.

<table border="0" cellpadding="0" cellspacing="0" width="969">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Yeast Extract</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">BactoPeptone</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Galactose</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;">Do not autoclave Galactose</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;">Growth medium</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;">For mitochondrial enrichment, you should use any non- fermentable carbon source, such as Galactose-based growth medium sterilized 1% Yeast Extract, 2% BactoPeptone, 2% Galactose</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">0.1 M TrisHCl pH9.4</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">30 mM TrisHCl pH7.6</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dithiothreitol (DTT)</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">&#160;10 mM DTT Buffer</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;">0.1 M TrisHCl pH 9.4, 10 mM Dithiothreitol (DTT). Make fresh every time</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">1.2 M Sorbitol</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">4 mM KH2PO4</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">16 mM K2HPO4</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">0.2&#956;m filter</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="46">
			<td height="46" style="height:46px;">Zymolyase Buffer&#160;</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;">1.2 M Sorbitol, 4 mM KH2PO4 , 16 mM K2HPO4. Filter this&#160; buffer (0.2&#956;m) and keep at room temperature for future use</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">&#160;Zymolyase 20T&#160;</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;">20,000 U/gr</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Recovery medium</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;">Galactose-based growth medium supplemented with 1 M Sorbitol</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">0.1 mg/mL Cycloheximide (CHX)</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">0.6 M Mannitol</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">5 mM MgAc</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">100 mM KCl</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">0.5 mg/mL Heparin</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">1 mM phenylmethanesulfonylfluoride (PMSF)</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Mannitol Buffer</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;">0.6 M Mannitol, 30 mM TrisHCl pH7.6, 5 mM MgAc, 100 mM KCl. Add freshly: 0.5 mg/mL Heparin, 0.1 mg/mL CHX and 1mM (PMSF). Filter this buffer and use it ice-cold</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">8M Guanidinium-HCl</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">&#160;100% and 70% Ethanol (EtOH)</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">&#160;3 M Sodium Acetate pH5.2</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">&#160;10 M LiCl stock solution</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">250 mM Tris HCl pH 6.8</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">SDS</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">&#160;Glycerol</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">&#946;-mercaptoethanol</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Bromophenolblue</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">&#160;4xLSB</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;">250 mM Tris HCl pH 6.8, 8% SDS, 40% Glycerol, 20% &#946;-mercaptoethanol and 0.02% Bromophenol blue</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Dounce homogenizer of 15-ml capacity equipped with tight- fitting pestle</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
		</tr>
	</tbody>
</table>

isolation of mrnas associated with yeast mitochondria to study mechanisms of localized translation

La maggior parte delle proteine ​​mitocondriali sono codificati nel nucleo e devono essere importati nel organello. Import può verificarsi durante la proteina è sintetizzata nei pressi dei mitocondri. Il supporto per questa possibilità deriva da studi recenti, in cui molti mRNA codificanti proteine ​​mitocondriali hanno dimostrato di essere localizzato nei pressi mitocondri. Insieme con dimostrazioni precedenti di associazione ribosomi &#39;con la membrana esterna, questi risultati suggeriscono un processo di traduzione localizzata. Tale traduzione localizzata può migliorare l&#39;efficienza di importazione, di fornire siti di regolazione unici e ridurre al minimo i casi di espressione ectopica. Diversi metodi sono stati utilizzati per caratterizzare i fattori ed elementi che mediano traduzione localizzata. Standard tra questi è frazionamento subcellulare mediante centrifugazione differenziale. Questo protocollo ha il vantaggio di isolamento di mRNA, ribosomi e proteine ​​in una singola procedura. Questi possono poi essere caratterizzata da diverse molecolare e biMetodi ochemical. Inoltre, trascrittomica e proteomica metodi possono essere applicati al materiale risultante, permettendo quindi intuizioni genoma di ampiezza. L&#39;utilizzo di lievito come organismo modello per tali studi ha i vantaggi di velocità, costi e semplicità. Inoltre, gli strumenti genetici avanzati e ceppi di delezione disponibili agevolare la verifica dei fattori candidati.

Questo protocollo permette la separazione di una frazione-mitocondri contenente da componenti citosolici. Il modo migliore per testare il suo successo è quello di eseguire l&#39;analisi del nord e l&#39;analisi occidentale (Figura 1) per i campioni delle diverse fasi di isolamento. Tre parametri per la qualità di isolamento sono derivati ​​da queste analisi. In primo luogo, se l&#39;RNA o proteine ​​nei campioni sono intatti - questi saranno rilevati come bande distinte nelle analisi. Eventi d...

Watch this Scientific Journal Video about Isolation of mRNAs Associated with Yeast Mitochondria to Study Mechanisms of Localized Translation at JoVE.com

Isolation of mRNAs Associated with Yeast Mitochondria to Study Mechanisms of Localized Translation

Molti mRNA codificanti proteine ​​mitocondriali sono associate alla membrana esterna mitocondriale. Descriviamo una procedura di frazionamento subcellulare volta a isolamento dei mitocondri di lievito con i suoi mRNA e ribosomi associati. Questo protocollo può essere applicato a cellule cresciute in condizioni diverse per rivelare meccanismi di localizzazione mRNA e traduzione localizzata vicino ai mitocondri.

Isolamento di mRNA associati con mitocondri di lievito per studiare i meccanismi di traduzione localizzata

Most of mitochondrial proteins are encoded in the nucleus and need to be imported into the organelle. Import may occur while the protein is synthesized ...

isolation-mrnas-associated-with-yeast-mitochondria-to-study

Research

JoVE Journal

Biology

12.8K Views.  Technion - Israel Institute of Technology.  Molti mRNA codificanti proteine ​​mitocondriali sono associate alla membrana esterna mitocondriale. Descriviamo una procedura di frazionamento subcellulare volta a isolamento dei mitocondri di lievito con i suoi mRNA e ribosomi associati. Questo protocollo può essere applicato a cellule cresciute in condizioni diverse per rivelare meccanismi di localizzazione mRNA e traduzione localizzata vicino ai mitocondri. 

Video: Isolation of mRNAs Associated with Yeast Mitochondria to Study Mechanisms of Localized Translation

Testing Visual Sensitivity to the Speed and Direction of Motion in Lizards

Testing visual sensitivity in any species provides basic information regarding behaviour, evolution, and ecology. However, testing specific features of the visual system provide more empirical evidence for functional applications. Investigation into the sensory system provides information about the sensory capacity, learning and memory ability, and establishes known baseline behaviour in which to gauge deviations (Burghardt, 1977). However, unlike mammalian or avian systems, testing for learning and memory in a reptile species is difficult. Furthermore, using an operant paradigm as a psychophysical measure of sensory ability is likewise as difficult. Historically, reptilian species have responded poorly to conditioning trials because of issues related to motivation, physiology, metabolism, and basic biological characteristics. Here, I demonstrate an operant paradigm used a novel model lizard species, the Jacky dragon (Amphibolurus muricatus) and describe how to test peripheral sensitivity to salient speed and motion characteristics. This method uses an innovative approach to assessing learning and sensory capacity in lizards. I employ the use of random-dot kinematograms (RDKs) to measure sensitivity to speed, and manipulate the level of signal strength by changing the proportion of dots moving in a coherent direction. RDKs do not represent a biologically meaningful stimulus, engages the visual system, and is a classic psychophysical tool used to measure sensitivity in humans and other animals. Here, RDKs are displayed to lizards using three video playback systems. Lizards are to select the direction (left or right) in which they perceive dots to be moving. Selection of the appropriate direction is reinforced by biologically important prey stimuli, simulated by computer-animated invertebrates.

Testing visual sensitivity in lizards using an operant conditioning paradigm that employs video playback of random-dot kinematograms and computer-generated invertebrates.

Test di sensibilità visiva alla velocità e direzione del movimento in lucertole

Testing visual sensitivity in any species provides basic information regarding behaviour, evolution, and ecology. However, testing specific features of ...

Ricerca

Biologia

Purification of Mitochondria from Yeast Cells

Mitochondria are the main site of ATP production during aerobic metabolism in eukaryotic non-photosynthetic cells1. These complex organelles also play essential roles in apoptotic cell death2, cell survival3, mammalian development4, neuronal development and function4, intracellular signalling5, and longevity regulation6. Our understanding of these complex biological processes controlled by mitochondria relies on robust methods for assessing their morphology, their protein and lipid composition, the integrity of their DNA, and their numerous vital functions. The budding yeast Saccharomyces cerevisiae, a genetically and biochemically manipulable unicellular eukaryote with annotated genome and well-defined proteome, is a valuable model for studying the molecular and cellular mechanisms underlying essential biological functions of mitochondria. For these types of studies, it is crucial to have highly pure mitochondria. Here we present a detailed description of a rapid and effective method for purification of yeast mitochondria. This method enables the isolation of highly pure mitochondria that are essentially free of contamination by other organelles and retain their structural and functional integrity after their purification. Mitochondria purified by this method are suitable for cell-free reconstitution of essential mitochondrial processes and can be used for the analysis of mitochondrial structure and functions, mitochondrial proteome and lipidome, and mitochondrial DNA.

We describe a rapid and effective method for purification of mitochondria from the yeast Saccharomyces cerevisiae. This method enables the high-yield isolation of pure mitochondria that are essentially free of contamination by other organelles and retain their structural and functional integrity after their purification.

Purificazione dei mitocondri da cellule di lievito

Mitochondria are the main site of ATP production during aerobic metabolism in eukaryotic non-photosynthetic cells1. These complex organelles also play ...

Isolation and Purification of Drosophila Peripheral Neurons by Magnetic Bead Sorting

The Drosophila peripheral nervous system (PNS) is a powerful model for investigating the complex processes of neuronal development and dendrite morphogenesis at the functional and molecular levels. To aid in these analyses, we have developed a strategy for the isolation of a subclass of PNS neurons called dendritic arborization (da) neurons that have been widely used for studying dendrite morphogenesis1,2. These neurons are very difficult to isolate as a pure population, due in part to their extremely low occurrence and their difficult-to-reach location below the tough chitinous larval cuticle. Our newly developed method overcomes these challenges, and is based on a fast and specific cell enrichment using antibody-coated magnetic beads. For our magnetic bead sorting studies, we have used age-matched third instar larvae expressing a mouse CD8 tagged GFP fusion protein (UAS-mCD8-GFP)3 under the control of either the class IV dendritic arborization (da) neuron-specific pickpocket (ppk)-GAL4 driver4 or the control of the pan-da neuron-specific GAL421-7 driver5. Although this protocol has been optimized for isolating PNS cells which are attached to the inner wall of the larval cuticle, by varying a few parameters, the same protocol could be used to isolate many different cell types attached to the cuticle at larval or pupal stages of development (e.g. epithelia, muscle, oenocytes etc.), or other cell types from larval organs depending upon the GAL4-specific driver expression pattern. The RNA isolated by this method is of high quality and can be readily used for downstream genomic analyses such as microarray gene expression profiling studies. This approach offers a powerful new tool to perform studies on isolated Drosophila dendritic arborization (da) neurons thereby providing novel insights into the molecular mechanisms underlying dendrite morphogenesis.

Isolation and Purification of Drosophila Peripheral Neurons by Magnetic Bead Sorting

In this video-article we present a method for the isolation and purification of Drosophila peripheral neurons using a fast magnetic bead assisted cell sorting strategy. RNA obtained from the isolated cells can be readily used for downstream applications including microarray analyses.

Isolamento e purificazione di Drosophila Neuroni periferici da Magnetic Ordinamento Bead

The Drosophila peripheral nervous system (PNS) is a powerful model for investigating the complex processes of neuronal development and dendrite ...

Visualization of Endoplasmic Reticulum Localized mRNAs in Mammalian Cells

In eukaryotes, most of the messenger RNAs (mRNAs) that encode secreted and membrane proteins are localized to the surface of the endoplasmic reticulum (ER). However, the visualization of these mRNAs can be challenging. This is especially true when only a fraction of the mRNA is ER-associated and their distribution to this organelle is obstructed by non-targeted (i.e. "free") transcripts. In order to monitor ER-associated mRNAs, we have developed a method in which cells are treated with a short exposure to a digitonin extraction solution that selectively permeabilizes the plasma membrane, and thus removes the cytoplasmic contents, while simultaneously maintaining the integrity of the ER. When this method is coupled with fluorescent in situ hybridization (FISH), one can clearly visualize ER-bound mRNAs by fluorescent microscopy. Using this protocol the degree of ER-association for either bulk poly(A) transcripts or specific mRNAs can be assessed and even quantified. In the process, one can use this assay to investigate the nature of mRNA-ER interactions.

Here we describe a method to visualize endoplasmic reticulum-associated mRNAs in mammalian tissue culture cells. This technique involves the selective permeabilization of the plasma membrane with digitonin to remove cytoplasmic contents followed by fluorescent in situ hybridization to detect either bulk poly(A) mRNA or specific transcripts.

Visualizzazione di mRNA reticolo endoplasmatico localizzate in cellule di mammifero

In eukaryotes, most of the messenger RNAs (mRNAs) that encode secreted and membrane proteins are localized to the surface of the endoplasmic reticulum ...

Confocal Imaging of Single Mitochondrial Superoxide Flashes in Intact Heart or In Vivo

Mitochondrion is a critical intracellular organelle responsible for energy production and intracellular signaling in eukaryotic systems. Mitochondrial dysfunction often accompanies and contributes to human disease. Majority of the approaches that have been developed to evaluate mitochondrial function and dysfunction are based on in vitro or ex vivo measurements. Results from these experiments have limited ability in determining mitochondrial function in vivo. Here, we describe a novel approach that utilizes confocal scanning microscopy for the imaging of intact tissues in live aminals, which allows the evaluation of single mitochondrial function in a real-time manner in vivo. First, we generate transgenic mice expressing the mitochondrial targeted superoxide indicator, circularly permuted yellow fluorescent protein (mt-cpYFP). Anesthetized mt-cpYFP mouse is fixed on a custom-made stage adaptor and time-lapse images are taken from the exposed skeletal muscles of the hindlimb. The mouse is subsequently sacrificed and the heart is set up for Langendorff perfusion with physiological solutions at 37 &deg;C. The perfused heart is positioned in a special chamber on the confocal microscope stage and gentle pressure is applied to immobilize the heart and suppress heart beat induced motion artifact. Superoxide flashes are detected by real-time 2D confocal imaging at a frequency of one frame per second. The perfusion solution can be modified to contain different respiration substrates or other fluorescent indicators. The perfusion can also be adjusted to produce disease models such as ischemia and reperfusion. This technique is a unique approach for determining the function of single mitochondrion in intact tissues and in vivo.

Confocal Imaging of Single Mitochondrial Superoxide Flashes in Intact Heart or In Vivo

Confocal scanning microscopy is applied for imaging single mitochondrial events in perfused heart or skeletal muscles in live animal. Real-time monitoring of single mitochondrial processes such as superoxide flashes and membrane potential fluctuations enables the evaluation of mitochondrial function in a physiologically relevant context and during pathological perturbations.

Imaging confocale delle singole mitocondriali superossido illumina di cuore intatto o<em&gt; In Vivo</em

Mitochondrion is a critical intracellular organelle responsible for energy production and intracellular signaling in eukaryotic systems. Mitochondrial ...

A Cell-Free Assay Using Xenopus laevis Embryo Extracts to Study Mechanisms of Nuclear Size Regulation

A fundamental question in cell biology is how cell and organelle sizes are regulated. It has long been recognized that the size of the nucleus generally scales with the size of the cell, notably during embryogenesis when dramatic reductions in both cell and nuclear sizes occur. Mechanisms of nuclear size regulation are largely unknown and may be relevant to cancer where altered nuclear size is a key diagnostic and prognostic parameter. In vivo approaches to identifying nuclear size regulators are complicated by the essential and complex nature of nuclear function. The in vitro approach described here to study nuclear size control takes advantage of the normal reductions in nuclear size that occur during Xenopus laevis development. First, nuclei are assembled in X. laevis egg extract. Then, these nuclei are isolated and resuspended in cytoplasm from late stage embryos. After a 30 - 90 min incubation period, nuclear surface area decreases by 20 - 60%, providing a useful assay to identify cytoplasmic components present in late stage embryos that contribute to developmental nuclear size scaling. A major advantage of this approach is the relative facility with which the egg and embryo extracts can be biochemically manipulated, allowing for the identification of novel proteins and activities that regulate nuclear size. As with any in vitro approach, validation of results in an in vivo system is important, and microinjection of X. laevis embryos is particularly appropriate for these studies.

A Cell-Free Assay Using Xenopus laevis Embryo Extracts to Study Mechanisms of Nuclear Size Regulation

Mechanisms of cellular and intra-cellular scaling remain elusive. The use of Xenopus embryo extracts has become increasingly common to elucidate mechanisms of organelle size regulation. This method describes embryo extract preparation and a novel nuclear scaling assay through which mechanisms of nuclear size regulation can be identified.

Un test cellulare gratuitamente utilizzando<em&gt; Laevis Xenopus</em&gt; Embryo Estrae per studiare i meccanismi del regolamento Size nucleare

A fundamental question in cell biology is how cell and organelle sizes are regulated. It has long been recognized that the size of the nucleus generally ...

Analysis of the Gap Junction-dependent Transfer of miRNA with 3D-FRAP Microscopy

Small antisense RNAs, like miRNA and siRNA, play an important role in cellular physiology and pathology and, moreover, can be used as therapeutic agents in the treatment of several diseases. The development of new, innovative strategies for miRNA/siRNA therapy is based on an extensive knowledge of the underlying mechanisms. Recent data suggest that small RNAs are exchanged between cells in a gap junction-dependent manner, thereby inducing gene regulatory effects in the recipient cell. Molecular biological techniques and flow cytometric analysis are commonly used to study the intercellular exchange of miRNA. However, these methods do not provide high temporal resolution, which is necessary when studying the gap junctional flux of molecules. Therefore, to investigate the impact of miRNA/siRNA as intercellular signaling molecules, novel tools are needed that will allow for the analysis of these small RNAs at the cellular level. The present protocol describes the application of three-dimensional fluorescence recovery after photobleaching (3D-FRAP) microscopy to elucidating the gap junction-dependent exchange of miRNA molecules between cardiac cells. Importantly, this straightforward and non-invasive live-cell imaging approach allows for the visualization and quantification of the gap junctional shuttling of fluorescently labeled small RNAs in real time, with high spatio-temporal resolution. The data obtained by 3D-FRAP confirm a novel pathway of intercellular gene regulation, where small RNAs act as signaling molecules within the intercellular network.

Here, we describe the application of three-dimensional fluorescence recovery after photobleaching (3D-FRAP) for the analysis of the gap junction-dependent shuttling of miRNA. In contrast to commonly applied methods, 3D-FRAP allows for the quantification of the intercellular transfer of small RNAs in real time, with high spatio-temporal resolution.

Analisi del trasferimento di gig Junction-dependent di miRNA con la microscopia 3D-FRAP

Small antisense RNAs, like miRNA and siRNA, play an important role in cellular physiology and pathology and, moreover, can be used as therapeutic agents ...

The Use of the Patch-Clamp Technique to Study the Thermogenic Capacity of Mitochondria

Mitochondrial thermogenesis (also known as mitochondrial uncoupling) is one of the most promising targets for increasing energy expenditure to combat metabolic syndrome. Thermogenic tissues such as brown and beige fats develop highly specialized mitochondria for heat production. Mitochondria of other tissues, which primarily produce ATP, also convert up to 25% of the total mitochondrial energy production into heat and can, therefore, have a considerable impact on the physiology of the whole body. Mitochondrial thermogenesis is not only essential for maintaining the body temperature, but also prevents diet-induced obesity and reduces the production of reactive oxygen species (ROS) to protect cells from oxidative damage. Since mitochondrial thermogenesis is a key regulator of cellular metabolism, a mechanistic understanding of this fundamental process will help in the development of therapeutic strategies to combat many pathologies associated with mitochondrial dysfunction. Importantly, the precise molecular mechanisms that control acute activation of thermogenesis in mitochondria are poorly defined. This lack of information is largely due to a dearth of methods for the direct measurement of uncoupling proteins. The recent development of patch-clamp methodology applied to mitochondria enabled, for the first time, the direct study of the phenomenon at the origin of mitochondrial thermogenesis, H+ leak through the IMM, and the first biophysical characterization of mitochondrial transporters responsible for it, the uncoupling protein 1 (UCP1), specific of brown and beige fats, and the ADP/ATP transporter (AAC) for all other tissues. This unique approach will provide new insights into the mechanisms that control H+ leak and mitochondrial thermogenesis and how they can be targeted to combat metabolic syndrome. This paper describes the patch-clamp methodology applied to mitochondria to study their thermogenic capacity by directly measuring H+ currents through the IMM.

This method article details the main steps in measuring H+ leak across the inner mitochondrial membrane with the patch-clamp technique, a new approach to study the thermogenic capacity of mitochondria.

L'uso della tecnica Patch-Clamp per studiare la capacità termogenica dei mitocondri

Mitochondrial thermogenesis (also known as mitochondrial uncoupling) is one of the most promising targets for increasing energy expenditure to combat ...

Application of Passive Head Motion to Generate Defined Accelerations at the Heads of Rodents

Exercise is widely recognized as effective for various diseases and physical disorders, including those related to brain dysfunction. However, molecular mechanisms behind the beneficial effects of exercise are poorly understood. Many physical workouts, particularly those classified as aerobic exercises such as jogging and walking, produce impulsive forces at the time of foot contact with the ground. Therefore, it was speculated that mechanical impact might be implicated in how exercise contributes to organismal homeostasis. For testing this hypothesis on the brain, a custom-designed ''passive head motion'' (hereafter referred to as PHM) system was developed that can generate vertical accelerations with controlled and defined magnitudes and modes and reproduce mechanical stimulation that might be applied to the heads of rodents during treadmill running at moderate velocities, a typical intervention to test the effects of exercise in animals. By using this system, it was demonstrated that PHM recapitulates the serotonin (5-hydroxytryptamine, hereafter referred to as 5-HT) receptor subtype 2A (5-HT2A) signaling in the prefrontal cortex (PFC) neurons of mice. This work provides detailed protocols for applying PHM and measuring its resultant mechanical accelerations at rodents' heads.

The present protocol describes a custom-designed ''passive head motion'' system, which reproduces mechanical accelerations at rodents' heads generated during their treadmill running at moderate velocities. It allows dissecting mechanical factors/elements from the beneficial effects of physical exercise.

Applicazione del movimento passivo della testa per generare accelerazioni definite alle teste dei roditori

Exercise is widely recognized as effective for various diseases and physical disorders, including those related to brain dysfunction. However, molecular ...

Isolation of Mitochondria from Mouse Skeletal Muscle for Respirometric Assays

Most of the cell&#39;s energy is obtained through the degradation of glucose, fatty acids, and amino acids by different pathways that converge on the mitochondrial oxidative phosphorylation (OXPHOS) system, which is regulated in response to cellular demands. The lipid molecule Coenzyme Q (CoQ) is essential in this process by transferring electrons to complex III in the electron transport chain (ETC) through constant oxidation/reduction cycles. Mitochondria status and, ultimately, cellular health can be assessed by measuring ETC oxygen consumption using respirometric assays. These studies are typically performed in established or primary cell lines that have been cultured for several days. In both cases, the respiration parameters obtained may have deviated from normal physiological conditions in&#160;any given organ or tissue.
Additionally, the intrinsic characteristics of cultured single fibers isolated from skeletal muscle impede this type of analysis. This paper presents an updated and detailed protocol for the analysis of respiration in freshly isolated mitochondria from mouse skeletal muscle. We also provide solutions to potential problems that could arise at any step of the process. The method presented here could be applied to compare oxygen consumption rates in diverse transgenic mouse models and study the mitochondrial response to drug treatments or other factors such as aging or sex. This is a feasible method to respond to crucial questions about mitochondrial bioenergetics metabolism and regulation.

Here, we describe a detailed method for mitochondria isolation from mouse skeletal muscle and the subsequent analysis of respiration by Oxygen Consumption Rate (OCR) using microplate-based respirometric assays. This pipeline can be applied to study the effects of multiple environmental or genetic interventions on mitochondrial metabolism.

Isolamento dei mitocondri dal muscolo scheletrico del topo per saggi respirometrici

Most of the cell&#39;s energy is obtained through the degradation of glucose, fatty acids, and amino acids by different pathways that converge on the ...