Agradecemos drs. Erez Eliyahu, Daniel Melamed, Ophry Pines e Doron Rapaport ajuda e comentários durante o estabelecimento deste protocolo. Este trabalho é financiado pelo ISF (número de concessão 1193-1109).

1. As mitocôndrias Purificação Pesa-se o sedimento de células. Aproximadamente 0,6 g é obtido a partir de 100 células ml. <ol><li> Crescer 100-150 ml de células de levedura para OD 600 = 1-1,5 em 30 ° C em um meio de crescimento não fermentável, tal como o meio de crescimento à base de galactose, de modo a enriquecer a mitocôndria. </li><li> Células de centrífuga a 3000 xg durante 5 min à temperatura ambiente e desprezar o sobrenadante. </li><li> Lave o pellet com água bidestilada e centrifugar novamente. Desprezar o sobrenadante. </li><li> Ressuspender o sedimento em 1 ml de tampão de DTT por 0,5 g de células. É importante para o tratamento das células com um agente de redução, a fim de quebrar as ligações dissulfureto dentro da parede da célula, aumentando assim a hidrólise. </li><li> Incubar as células durante 10 min a 30 ° C com agitação suave. Enquanto isso, a pesar de 6 mg Zymolyase por 1 g de células e suspendê-lo em Zymolyase Buffer. </li><li> Células de centrífuga a 3000 xg durante 5 minutos, umatemperatura ambiente t e descartar o sobrenadante. </li><li> Ressuspender o sedimento em 1 ml de Tampão de Zymolyase por 0,15 g de células. Não vórtice. </li><li> Medida OD600 de 10 uL alíquotas de células em 990 ul de água. </li><li> Adicionar Zymolyase (passo 1.5) para as células para hidrolisar os polímeros de glicose aos β-1 ,3-glucano de ligações e gerar esferoplastos. A partir deste passo, esferoplastos deve ser mantida numa solução isotónica, a fim de evitar lise. </li><li> Incubar as células durante 15 min a 30 ° C (para a actividade óptima de Zymolyase) com agitação suave. Para verificar a hidrólise da parede celular e geração de esferoplastos, misturar 10 mL de células com 990 ul de água. Os esferoplastos são esperados para lisar devido à diferença osmótico, e o OD 600 deve ser pelo menos 10 vezes menor do que o valor determinado no passo 1.9. Se não, continue a incubação com Zymolyase por mais 15 min. </li><li> Células de centrífuga a 3000 xg durante 5 min à temperatura ambiente. Dis Cuidadosamentecartão do sobrenadante, o sedimento como pode ser instável. </li><li> Lave esferoplastos com Zymolyase buffer e descartar o sobrenadante. </li><li> Ressuspender esferoplastos com 100 ml meio de recuperação. Transferir esferoplastos para um balão Erlenmeyer e incubar durante 1 hora a 30 ° C com agitação. Este passo de recuperação é necessário uma vez que durante a tradução tratamento Zymolyase é preso e localização do mRNA é interrompido (Figura 1B). </li><li> Adicionar 0,1 mg / ml CHX e esferoplastos de transferência para uma de 50 ml pré-resfriada tubo cônico. Além CHX é importante para congelar associação dos ribossomos com mRNAs. Assim, a associação mRNA ribossomos dependentes com mitocôndrias é mantida. </li><li> Esferoplastos Centrifugar a 3.000 xg durante 5 min a 4 ° C e desprezar o sobrenadante. </li><li> Lavar duas vezes com frio manitol Buffer. </li><li> Ressuspender esferoplastos com 4 ml frio manitol buffer e transferi-los para um homogeneizador Dounce de 15 ml de capacidade equipado com ajuste apertadopilão. Gentilmente quebrar esferoplastos com 15 tacadas e transferir o lisado para um tubo de 13 ml. </li><li> Centrifuga-se o lisado a 1,500 xg durante 6 minutos a 4 ° C para sedimentar os núcleos e as células intactas. </li><li> Transferir cuidadosamente o sobrenadante para um novo tubo. Separe 1 ml (25%) da amostra como uma amostra não fracionada (amostra &quot;Total&quot;). Transferência de 50 mL desta amostra para um novo tubo e adicionar 15 ml de 4X LSB para análise de Western blot. O precipitado de RNA a partir do resto da amostra &quot;total&quot; (Ver Protocolo 3, a precipitação do RNA). </li><li> Centrifugar o sobrenadante a 10.000 xg durante 10 min a 4 ° C para sedimentar as mitocôndrias. </li><li> Transferir o sobrenadante (~ 3 mL) para um tubo novo e mantê-lo em gelo. Esta é a fracção &quot;citosólica&quot;. Transferência de 50 mL desta amostra para um novo tubo e adicionar 15 ml de 4x LSB para análise de Western blot. O precipitado de RNA a partir do resto da amostra &quot;citosólica&quot; (Ver Protocol 3, RNA de precipitação). </li><li> Lava-se a pelete com 3 ml de tampão de manitol e centrifugar novamente a 10.000 xg durante 10 min a 4 ° C. </li><li> Ressuspender o sedimento em 3 ml de tampão de manitol. Este exemplo contém a mitocôndria, e referido como fração &quot;mitocôndrias&quot;. Transferência de 50 mL desta amostra para um novo tubo e adicionar 15 ml de 4x LSB para análise de Western blot. </li></ol> 2. Extração de RNA <ol><li> Adicionar a cada amostra de um volume de 8 M de guanidina-HCl e dois volumes de etanol a 100%. Vortex e incubar durante pelo menos 2 horas a -20 ° C. </li><li> Centrifugar as amostras a 10.000 xg durante 20 min a 4 ° C. Elimine o sobrenadante. Tenha cuidado, pois o pellet pode ser instável. </li><li> Lavar o sedimento com 70% de EtOH. </li><li> Ressuspender o sedimento em 400 ml de água isenta de RNase e transferir a amostra para um novo tubo de Eppendorf. </li><li> Precipitar o ARN de novo por adição de 0,1 volume de 3 M de sódio acetate pH 5,2 e dois volumes de EtOH a 100%. Vortex e incubar durante pelo menos 2 horas a -20 ° C. </li><li> Centrifugar as amostras a 20.000 xg durante 20 min a 4 ° C. Descartar o sobrenadante e lava-se com EtOH a 70%. </li><li> O ar seco do pellet e ressuspender com água RNase-free. As amostras de RNA a -80 loja ° C. As amostras podem ser utilizadas para a análise Northern ou análise de microarray 19 18 (ver Protocolo 3). </li></ol> 3. Preparando o RNA para Análise Microarray <ol><li> Ressuspender o mRNA a partir do passo 2,2, com 650 ml de água isenta de RNase. </li><li> Para remover qualquer ADN residual ou proteínas, adicionar um volume igual (650 mL) de ácido fenol: clorofórmio (5:1, pH 4,7) e vórtex vigorosamente. Centrifugar a velocidade máxima por 2 min. </li><li> Transferir 500 ml da fase superior (fase aquosa) para um tubo novo. Evite tomar a interfase, pois ele contém DNA. Também deve ter cuidado de tomar fenol, o que pode inibir a reação de transcrição reversa. &lt;/ Li&gt; <li> A amostra de ARN contém uma quantidade significativa de heparina, que é um potente inibidor da transcriptase inversa. Assim, por RT-PCR ou rotulagem microarray que precisa ser removida. Retirar heparina por LiCl precipitação: adicionar LiCl até uma concentração final de 2 M e incuba-se as amostras durante a noite a -20 ° C. </li><li> Descongelar as amostras a 4 ° C e centrifuga-se a 20000 xg durante 20 min a 4 ° C. </li><li> Descartar cuidadosamente o sobrenadante e lavar o sedimento com etanol a 80%. Centrifugar novamente como descrito na etapa 3.5. </li><li> Rejeitar o sobrenadante, o ar seco e ressuspender o sedimento em 150 ml de água isenta de RNase. </li><li> Para remover qualquer LiCl residual precipitar novamente com 0,1 volume de 3 M acetato de sódio pH 5,3 e 3 volumes de etanol a 100%. Incubar a -20 ° C durante pelo menos 2 horas. </li><li> Centrifugar a velocidade máxima por 20 min a 4 ° C. Lavar cuidadosamente a pelete transparente com etanol a 80% e ar seco. </li><li> Ressuspender opellet com 25 ml de água livre de RNase e manter as amostras a -80 ° C. </li><li> Siga os passos para a rotulagem RNA e hibridização descrito em 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>

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Os avanços tecnológicos no processamento de imagens tinha rendido ferramentas de alta resolução para estudar a localização mRNA. Hoje, pode-se medir o movimento de mesmo uma única molécula de mRNA na escala de tempo ms 23-26. No entanto, as abordagens bioquímicas tradicionais, como os descritos acima, também são informativos e são preferíveis em alguns casos. Isolamento bioquímico permite a purificação de um grande reportório de ARNm e proteínas, e por isso é preferível para estudos genôm...

As células eucarióticas são organizados em compartimentos distintos que possuem funções específicas. Para cumprir a sua função, cada compartimento contém um conjunto exclusivo de proteínas que são essenciais para a sua actividade. Um possível mecanismo pelo qual estas proteínas se aproximam de seu compartimento é de 1,2 localizada tradução. Neste processo, a proteína é sintetizada no destino por ribossomas e mRNAs que são aí localizados. Entre as vantagens prováveis ​​de tradução localizada são o aumento da eficiência do direcionamento de proteínas, diminuição da necessidade de acompanhantes de proteína, e permitindo que os mecanismos de regulação específicas do site. Além disso, mRNAs e ribossomas localizados podem ser um reservatório isolado de máquinas de tradução em casos de estresse celular, quando a tradução geral é inibida. As mitocôndrias se tornou nos últimos anos um modelo central para estudar tradução localizada. A maioria das proteínas de mitocôndrias são codificadas no núcleo, traduzida no citoplasma,e importadas para a organela. Várias linhas de evidência indicam que muitas destas proteínas são produzidas através de um processo de tradução local. Inicialmente, os estudos de microscopia eletrônica e de fracionamento bioquímico detectado ribossomos associados mitocôndrias 3-5. Estes estudos, onde, em seguida, corroborado in vivo pelo trabalho em mRNAs específicos, que foram encontrados para ser importados em um 6,7 maneira cotranslational. Estudos genômicos de mRNAs associação com mitocôndrias revelou que uma fracção significativa dos mRNAs são localizadas na vizinhança mitocôndrias 8-10. Alguns destes mRNAs foram adicionalmente caracterizados in vivo por métodos de fluorescência, tais como peixes ou MTAG 9,11. A interpretação direta desta associação é que esses mRNAs servir como modelos para tradução localizada. Os mecanismos pelos quais estas se aproximam dos mRNAs mitocôndrias são desconhecidas. Domínios não-codificante (mais significantly 3 &#39;UTRs) mostraram estar envolvidas na associação de mRNA para a mitocôndria 12. Estes domínios são susceptíveis de servir como um local de ligação a proteínas de ligação a ARN que medeiam o seu transporte. Estudos em levedura revelou que um membro da família de proteínas de PUM (Puf3) apoia associação ARNm com mitocôndrias 8,13. Um papel plausível para Puf3, que se baseia em funções de outros membros da família, é para inibir a tradução do mRNA, enquanto está a caminho 14. Assim, os mRNAs podem ser transportados num estado não traduzida, por proteínas de ligação de ARN que interagem com regiões não codificantes. Alternativamente, um grande corpo de trabalho sugere que ocorre o transporte, enquanto a proteína está a ser sintetizado. Em particular, os inibidores de tradução foram mostrados para afetar mRNAs associação 8,13. Além disso, os recursos traduzidos como a agosto, a sequência de direcionamento mitocondrial (MTS) ou regiões ORF foram mostrados para ajudar na localização 8,11,15. Ch proteína Hsp70-famíliaaperone e receptor de proteína de membrana externa as mitocôndrias foram também demonstrado que suporta associação ARNm, implicando que mais características codificado em proteínas são importantes para a localização de mRNA 16. Isto é consistente com um modelo no qual a proteína-ribossoma emergente serve como elemento de reconhecimento para a segmentação complexo ribossoma-ARNm-proteína para a mitocôndria 17. Tradução localizada perto da mitocôndria foi estudado por vários métodos, incluindo a microscopia de electrões (para visualizar ribossomas) 3, FISH 9, RNA verde (para detectar os mRNAs específicos) 11, e fraccionamento bioquímico (para detectar os níveis de RNA e ribossomas) 10,18. Enquanto os métodos anteriores detectar a localização in vivo e pode permitir a visualização dinâmica de transporte, este último permite a detecção de vários mRNAs diferentes em uma única experiência. Além disso, para codificação de fracionamento bioquímico ou não-codificantes domínios não precisa ser altrado, por conseguinte, as suas funções específicas, podem ser avaliadas. Fraccionamento bioquímico tem sido utilizado com sucesso durante muitos anos, para o isolamento de diversos compartimentos celulares diferentes. Seus princípios e limitações estão bem estabelecidos, e pode-se facilmente modificar os protocolos existentes para finalidade diferente. A instrumentação necessária é padrão em muitos laboratórios, portanto, é geralmente o primeiro método de escolha para estudar a localização intracelular. Descreve-se um protocolo que foi optimizado para o isolamento de ARNm, enquanto ribossomas estão associados com a mitocôndria. Este protocolo é, portanto, ideal para o estudo de fatores envolvidos na tradução localizada perto mitocôndria.

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			<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>
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			<td style="width:119px;"></td>
			<td style="width:563px;">Do not autoclave Galactose</td>
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			<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>
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			<td height="21" style="height:21px;">0.1 M TrisHCl pH9.4</td>
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			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
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			<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>
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			<td height="21" style="height:21px;">Dithiothreitol (DTT)</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
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			<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>
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			<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>
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			<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>
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			<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>
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			<td height="21" style="height:21px;width:216px;">0.2&#956;m filter</td>
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			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
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			<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>
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			<td height="21" style="height:21px;">&#160;Zymolyase 20T&#160;</td>
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			<td style="width:119px;"></td>
			<td style="width:563px;">20,000 U/gr</td>
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		<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>
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		<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>
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		<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>
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			<td height="21" style="height:21px;">&#160;Glycerol</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:563px;"></td>
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		<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>
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isolation of mrnas associated with yeast mitochondria to study mechanisms of localized translation

A maioria das proteínas mitocondriais são codificados no núcleo e precisam ser importadas para a organela. Import pode ocorrer enquanto que a proteína é sintetizada próximo da mitocôndria. O suporte para esta possibilidade é derivado de estudos recentes, em que muitos mRNAs que codificam proteínas mitocondriais foram mostrados para ser localizado para a vizinhança mitocôndria. Juntamente com as demonstrações anteriores de associação dos ribossomos com a membrana externa, estes resultados sugerem um processo de tradução localizada. Tal tradução localizada pode melhorar a eficiência de importação, fornecer locais únicos de regulação e minimizar os casos de expressão ectópica. Diversos métodos têm sido utilizados para caracterizar os elementos e elementos que medeiam a tradução localizado. Padrão entre estes é o fraccionamento subcelular por centrifugação diferencial. Este protocolo apresenta a vantagem de isolamento de ARNm, ribossomas e proteínas num único processo. Estes podem, então, ser caracterizada por vários molecular e bimétodos ochemical. Além disso, transcriptómica e proteómica métodos pode ser aplicada ao material resultante, assim, permitir percepções de todo o genoma. A utilização de leveduras como organismo-modelo para tais estudos tem as vantagens de rapidez, simplicidade e custos. Além disso, as ferramentas genéticas avançadas e estirpes de deleção disponíveis facilitar a verificação de factores candidatos.

Este protocolo permite a separação de uma fracção contendo mitocôndrias de componentes citosólicos. A melhor maneira de testar o seu êxito é realizar análise Northern e análise de Western (Figura 1) a partir de amostras dos diferentes passos de isolamento. Três parâmetros para a qualidade de isolamento são derivadas a partir destas análises. Em primeiro lugar, quando o RNA ou proteínas nas amostras estão intactos - estes serão detectados como bandas distintas nas análises. Eventos de 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

Muitos mRNAs que codificam as proteínas mitocondriais são associados com a membrana exterior mitocondrial. Descreve-se um processo de fracionamento subcelular que visa o isolamento de mitocôndrias de levedura com seus mRNAs e ribossomos associados. Este protocolo pode ser aplicado a células cultivadas sob diversas condições, a fim de revelar os mecanismos de localização de mRNA e tradução localizada perto das mitocôndrias.

Isolamento de mRNAs Associated com mitocôndrias de levedura para estudar mecanismos de regionalização de Tradução

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 visualizações.  Technion - Israel Institute of Technology.  Muitos mRNAs que codificam as proteínas mitocondriais são associados com a membrana exterior mitocondrial. Descreve-se um processo de fracionamento subcelular que visa o isolamento de mitocôndrias de levedura com seus mRNAs e ribossomos associados. Este protocolo pode ser aplicado a células cultivadas sob diversas condições, a fim de revelar os mecanismos de localização de mRNA e tradução localizada perto das mitocôndrias. 

Vídeo: 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.

Teste de sensibilidade visual para a velocidade e direção do movimento em Lagartos

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

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.

Purificação de mitocôndrias de células de levedura

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 purificação de Drosophila Neurônios periféricos por classificação Bead Magnética

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.

Visualização de mRNAs retículo endoplasmático localizados em células de mamíferos

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.

Imagem confocal de Solteiro mitocondriais superóxido Pisca em coração intacto ou<em&gt; In Vivo</em

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

Isolation and Functional Analysis of Mitochondria from Cultured Cells and Mouse Tissue

Comparison between two or more distinct groups, such as healthy vs. disease, is necessary to determine cellular status. Mitochondria are at the nexus of cell heath due to their role in both cell metabolism and energy production as well as control of apoptosis. Therefore, direct evaluation of isolated mitochondria and mitochondrial perturbation offers the ability to determine if organelle-specific (dys)function is occurring. The methods described in this protocol include isolation of intact, functional mitochondria from HEK cultured cells and mouse liver and spinal cord, but can be easily adapted for use with other cultured cells or animal tissues. Mitochondrial function assessed by TMRE and the use of common mitochondrial uncouplers and inhibitors in conjunction with a fluorescent plate reader allow this protocol not only to be versatile and accessible to most research laboratories, but also offers high throughput.

Comparison of mitochondrial membrane potential between samples yields valuable information about cellular status. Detailed steps for isolating mitochondria and assessing response to inhibitors and uncouplers using fluorescence are described. The method and utility of this protocol are illustrated by use of a cell culture and animal model of cellular stress.

Isolamento e Análise Funcional de mitocôndrias de células cultivadas e mouse Tissue

Comparison between two or more distinct groups, such as healthy vs. disease, is necessary to determine cellular status. Mitochondria are at the nexus of ...

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.

Um ensaio-Free Cell Usando<em&gt; Xenopus laevis</em&gt; Embryo Extrai para estudar mecanismos de regulação Tamanho Nuclear

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.

Análise do Gap Junction-dependente Transferência de miARN com 3D-FRAP Microscopia

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.

O uso da técnica de grampo de remendo para estudar a capacidade termogênica das mitocôndrias

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.

Aplicação do movimento passivo da cabeça para gerar acelerações definidas nas cabeças dos roedores

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