Name: use of time-lapse microscopy and stage-specific nuclear depletion of proteins to study meiosis in s. cerevisiae
Uploaded: 2022-10-11T14:40:00
Description: Watch this Scientific Journal Video about Use of Time-Lapse Microscopy and Stage-Specific Nuclear Depletion of Proteins to Study Meiosis in S. cerevisiae at JoVE.com

We bedanken het Light Microscopy Imaging Center aan de Indiana University. Dit werk werd ondersteund door een subsidie van de National Institutes of Health (GM105755).

1. Voorbereiding van de benodigde materialen
<ol><li>Bereid reagentia voor op de groei en sporulatie van gistcellen. OPMERKING: Als ontluikende giststammen ade2- en trp1- zijn, vul dan alle media aan in stap 1.1.1-1.1.3 met een eindconcentratie van 0,01% adenine en 0,01% tryptofaan uit 1% voorraden. Als u media steriliseert door autoclaaf, voeg deze aminozuren dan pas toe nadat de reagentia zijn geautoclaveerd en tot kamertemperatuur zijn afgekoeld.<ol><li>Bereid voor vegetatieve g...

<ol>
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M., Lacefield, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+requirement+for+Bub1+and+Bub3+in+regulation+of+meiotic+versus+mitotic+chromosome+segregation.">Differential requirement for Bub1 and Bub3 in regulation of meiotic versus mitotic chromosome segregation.</a> Journal of Cell Biology. 219 (4), 201909136 (2020).</li><li>van Werven, F. J., Amon, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+entry+into+gametogenesis.">Regulation of entry into gametogenesis.</a> Philosophical Transactions of the Royal Society London B: Biological Sciences. 366 (1584), 3521-3531 (2011).</li><li>Carlile, T. M., Amon, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Meiosis+I+is+established+through+division-specific+translational+control+of+a+cyclin.">Meiosis I is established through division-specific translational control of a cyclin.</a> Cell. 133 (2), 280-291 (2008).</li><li>Benjamin, K. R., Zhang, C., Shokat, K. M., Herskowitz, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+landmark+events+in+meiosis+by+the+CDK+Cdc28+and+the+meiosis-specific+kinase+Ime2.">Control of landmark events in meiosis by the CDK Cdc28 and the meiosis-specific kinase Ime2.</a> Genes and Development. 17 (12), 1524-1539 (2003).</li><li>Xu, L., Ajimura, M., Padmore, R., Klein, C., Kleckner, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NDT80,+a+meiosis-specific+gene+required+for+exit+from+pachytene+in+Saccharomyces+cerevisiae.">NDT80, a meiosis-specific gene required for exit from pachytene in Saccharomyces cerevisiae.</a> Molecular and Cellular Biology. 15 (12), 6572-6581 (1995).</li><li>Chu, S., Herskowitz, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gametogenesis+in+yeast+is+regulated+by+a+transcriptional+cascade+dependent+on+Ndt80.">Gametogenesis in yeast is regulated by a transcriptional cascade dependent on Ndt80.</a> Molecular Cell. 1 (5), 685-696 (1998).</li><li>Haruki, H., Nishikawa, J., Laemmli, U. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+anchor-away+technique:+rapid,+conditional+establishment+of+yeast+mutant+phenotypes.">The anchor-away technique: rapid, conditional establishment of yeast mutant phenotypes.</a> Molecular Cell. 31 (6), 925-932 (2008).</li><li>Borek, W. 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=The+proteomic+landscape+of+centromeric+chromatin+reveals+an+essential+role+for+the+Ctf19(CCAN)+complex+in+meiotic+kinetochore+assembly.">The proteomic landscape of centromeric chromatin reveals an essential role for the Ctf19(CCAN) complex in meiotic kinetochore assembly.</a> Current Biology. 31 (2), 283-296 (2021).</li><li>Mehta, G. D., Agarwal, M., Ghosh, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+characterization+of+kinetochore+protein,+Ctf19+in+meiosis+I:+an+implication+of+differential+impact+of+Ctf19+on+the+assembly+of+mitotic+and+meiotic+kinetochores+in+Saccharomyces+cerevisiae.">Functional characterization of kinetochore protein, Ctf19 in meiosis I: an implication of differential impact of Ctf19 on the assembly of mitotic and meiotic kinetochores in Saccharomyces cerevisiae.</a> Molecular Microbiology. 91 (6), 1179-1199 (2014).</li><li>Ortiz, J., Stemmann, O., Rank, S., Lechner, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+putative+protein+complex+consisting+of+Ctf19,+Mcm21,+and+Okp1+represents+a+missing+link+in+the+budding+yeast+kinetochore.">A putative protein complex consisting of Ctf19, Mcm21, and Okp1 represents a missing link in the budding yeast kinetochore.</a> Genes and Development. 13 (9), 1140-1155 (1999).</li><li>Hyland, K. M., Kingsbury, J., Koshland, D., Hieter, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ctf19p:+A+novel+kinetochore+protein+in+Saccharomyces+cerevisiae+and+a+potential+link+between+the+kinetochore+and+mitotic+spindle.">Ctf19p: A novel kinetochore protein in Saccharomyces cerevisiae and a potential link between the kinetochore and mitotic spindle.</a> Journal of Cell Biology. 145 (1), 15-28 (1999).</li><li>Fernius, J., Marston, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Establishment+of+cohesion+at+the+pericentromere+by+the+Ctf19+kinetochore+subcomplex+and+the+replication+fork-associated+factor,+Csm3.">Establishment of cohesion at the pericentromere by the Ctf19 kinetochore subcomplex and the replication fork-associated factor, Csm3.</a> PLoS Genetics. 5 (9), 1000629 (2009).</li><li>Meyer, R. 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=Ipl1/Aurora-B+is+necessary+for+kinetochore+restructuring+in+meiosis+I+in+Saccharomyces+cerevisiae.">Ipl1/Aurora-B is necessary for kinetochore restructuring in meiosis I in Saccharomyces cerevisiae.</a> Molecular Biology of the Cell. 26 (17), 2986-3000 (2015).</li><li>Elrod, S. L., Chen, S. M., Schwartz, K., Shuster, E. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimizing+sporulation+conditions+for+different+Saccharomyces+cerevisiae+strain+backgrounds.">Optimizing sporulation conditions for different Saccharomyces cerevisiae strain backgrounds.</a> Methods in Molecular Biology. 557, 21-26 (2009).</li><li>Deutschbauer, A. M., Davis, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+trait+loci+mapped+to+single-nucleotide+resolution+in+yeast.">Quantitative trait loci mapped to single-nucleotide resolution in yeast.</a> Nature Genetics. 37 (12), 1333-1340 (2005).</li><li>Ben-Ari, G., 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=Four+linked+genes+participate+in+controlling+sporulation+efficiency+in+budding+yeast.">Four linked genes participate in controlling sporulation efficiency in budding yeast.</a> PLoS Genetics. 2 (11), 195 (2006).</li><li>Primig, 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=The+core+meiotic+transcriptome+in+budding+yeasts.">The core meiotic transcriptome in budding yeasts.</a> Nature Genetics. 26 (4), 415-423 (2000).</li><li>Spencer, F., Gerring, S. L., Connelly, C., Hieter, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitotic+chromosome+transmission+fidelity+mutants+in+Saccharomyces+cerevisiae.">Mitotic chromosome transmission fidelity mutants in Saccharomyces cerevisiae.</a> Genetics. 124 (2), 237-249 (1990).</li><li>Weinhandl, K., Winkler, M., Glieder, A., Camattari, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Carbon+source+dependent+promoters+in+yeasts.">Carbon source dependent promoters in yeasts.</a> Microbial Cell Factories. 13, 5 (2014).</li><li>Byers, B., Goetsch, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reversible+pachytene+arrest+of+Saccharomyces+cerevisiae+at+elevated+temperature.">Reversible pachytene arrest of Saccharomyces cerevisiae at elevated temperature.</a> Molecular and General Genetics. 187 (1), 47-53 (1982).</li><li>Winter, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Sum1/Ndt80+transcriptional+switch+and+commitment+to+meiosis+in+Saccharomyces+cerevisiae.">The Sum1/Ndt80 transcriptional switch and commitment to meiosis in Saccharomyces cerevisiae.</a> Microbiology and Molecular Biology Reviews. 76 (1), 1-15 (2012).</li><li>Neiman, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sporulation+in+the+budding+yeast+Saccharomyces+cerevisiae.">Sporulation in the budding yeast Saccharomyces cerevisiae.</a> Genetics. 189 (3), 737-765 (2011).</li><li>Robinett, C., 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=C.+al.+In+vivo+localization+of+DNA+sequences+and+visualization+of+large-scale+chromatin+organization+using+lac+operator/repressor+recognition.">C. al. In vivo localization of DNA sequences and visualization of large-scale chromatin organization using lac operator/repressor recognition.</a> Journal of Cell Biology. 135, 1685-1700 (1996).</li><li>Straight, A. F., Belmont, A. S., Robinett, C. C., Murray, A. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=GFP+tagging+of+budding+yeast+chromosomes+reveals+that+protein-protein+interactions+can+mediate+sister+chromatid+cohesion.">GFP tagging of budding yeast chromosomes reveals that protein-protein interactions can mediate sister chromatid cohesion.</a> Current Biology. 6 (12), 1599-1608 (1996).</li><li>Sym, M., Engebrecht, J. A., Roeder, G. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ZIP1+is+a+synaptonemal+complex+protein+required+for+meiotic+chromosome+synapsis.">ZIP1 is a synaptonemal complex protein required for meiotic chromosome synapsis.</a> Cell. 72 (3), 365-378 (1993).</li><li>Scherthan, H., 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=Chromosome+mobility+during+meiotic+prophase+in+Saccharomyces+cerevisiae.">Chromosome mobility during meiotic prophase in Saccharomyces cerevisiae.</a> Proceedings of the National Academy of Sciences of the United States of America. 104 (43), 16934-16939 (2007).</li></ol>

Dit protocol combineert het NDT80-in-systeem om cellen te synchroniseren, de ankerwegtechniek om eiwitten uit de kern uit te putten en fluorescentie time-lapse-microscopie om ontluikende gistcellen tijdens meiose in beeld te brengen. Het NDT80-in systeem is een methode voor meiotische celcyclussynchronisatie die gebruik maakt van een profase I arrest en release 4,8. Hoewel individuele cellen enigszins zullen variëren in de hoeveelheid tijd die ...

Time-lapse fluorescentiemicroscopie is een waardevol hulpmiddel voor het bestuderen van de dynamiek van meiotische chromosoomsegregatie in ontluikende gist 1,2. Ontluikende gistcellen kunnen worden geïnduceerd om meiose te ondergaan door uithongering van belangrijke voedingsstoffen3. Tijdens meiose ondergaan cellen één ronde van chromosoomsegregatie gevolgd door twee delingen om vier meiotische producten te creëren die in sporen zijn verpakt (figuur 1). Individuele cellen kunnen worden gevisualiseerd in elk stadium van meiose, wat ruimtelijke en temporele gegevens genereert die gemakkelijk kunnen worden gemist door beeldvorming met vaste cellen. Dit protocol laat zien hoe het combineren van time-lapse fluorescentiemicroscopie met twee eerder vastgestelde methoden, het induceerbare NDT80-systeem (NDT80-in) en de ankerwegtechniek, kan worden gebruikt om de functie van specifieke eiwitten in verschillende meiotische stadia te bestuderen.
Het NDT80-in systeem is een krachtig hulpmiddel voor meiotische celcyclussynchronisatie dat vertrouwt op de induceerbare expressie van de transcriptiefactor van de middelste meiose NDT80 4,5. NDT80-expressie is vereist voor profase I-uitgang 6,7. Met het NDT80-in-systeem staat NDT80 onder controle van de GAL1-10-promotor in cellen die de Gal4-transcriptiefactor tot expressie brengen die is gefuseerd tot een oestrogeenreceptor (Gal4-ER)4,5. Omdat Gal4-ER alleen de kern binnenkomt wanneer het gebonden is aan β-oestradiol, arresteren NDT80-in-cellen in profase I bij afwezigheid van β-oestradiol, wat de synchronisatie van cellen in profase I mogelijk maakt (figuur 1). β-oestradioltoevoeging bevordert de translocatie van de Gal4-ER transcriptiefactor in de kern, waar het GAL1-10 bindt om de expressie van NDT80 aan te drijven, wat leidt tot synchrone toegang tot de meiotische delingen. Hoewel time-lapse microscopie zonder synchronisatie kan worden uitgevoerd, is het voordeel van het gebruik van synchronisatie de mogelijkheid om een remmer of een medicijn toe te voegen terwijl cellen zich in een specifiek stadium van meiose bevinden.
De anker weg techniek is een induceerbaar systeem waarbij een eiwit uit de kern kan worden uitgeput met de toevoeging van rapamycine8. Deze techniek is ideaal voor het bestuderen van nucleaire eiwitten tijdens celdeling in ontluikende gist omdat gistcellen gesloten mitose en meiose ondergaan, waarbij de nucleaire envelop niet afbreekt. Bovendien is deze techniek zeer nuttig voor eiwitten die meerdere functies hebben tijdens meiose. In tegenstelling tot deleties, mutante allelen of meiotische nul-allelen, brengt het verwijderen van een doeleiwit uit de kern in een specifiek stadium de doeleiwitactiviteit in eerdere stadia niet in gevaar, waardoor een nauwkeuriger interpretatie van de resultaten mogelijk is. Het ankersysteem maakt gebruik van het sluiten van ribosomale subeenheden tussen de kern en het cytoplasma die optreedt bij ribosomale rijping8. Om het doeleiwit uit de kern uit te putten, wordt het doeleiwit gelabeld met het FKBP12-rapamycine-bindingsdomein (FRB) in een stam waarin de ribosomale subeenheid Rpl13A is gelabeld met FKBP12. Zonder rapamycine werken FRB en FKBP12 niet op elkaar in en blijft het FRB-gelabelde eiwit in de kern. Bij toevoeging aan rapamycine vormt de rapamycine een stabiel complex met FKBP12 en FRB, en het complex wordt uit de kern gehaald vanwege de interactie met Rpl13A (figuur 1). Om celdood bij toevoeging van rapamycine te voorkomen, herbergen cellen de tor1-1-mutatie van het TOR1-gen . Bovendien bevatten deze cellen fpr1Δ, een nulallel van het S. cerevisiae FKBP12-eiwit, dat voorkomt dat endogene Fpr1 Rpl13A-FKBP12 voor FRB- en rapamycinebinding uitconcurreert. De ankerachtergrondmutaties, tor1-1 en fpr1Δ, hebben geen invloed op meiotische timings of chromosoomsegregatie2.
Om het nut van deze techniek aan te tonen, werd het kinetochore-eiwit Ctf19 op verschillende tijdstippen tijdens meiose uitgeput. Ctf19 is een component van het kinetochore dat overbodig is bij mitose, maar vereist is voor een goede chromosoomsegregatie bij meiose 9,10,11,12,13. Bij meiose wordt het kinetochore afgeworpen in profase I en ctf19 is belangrijk voor kinetochore re-assembly 9,14. Voor dit protocol werden cellen met het NDT80-in-systeem gesynchroniseerd en werd de ankerwegtechniek gebruikt om het doeleiwit Ctf19 uit de kern uit te putten voor en na de afgifte uit profase I en na meiose I-chromosoomsegregatie (figuur 1). Dit protocol kan worden aangepast om andere eiwitten van belang in elk stadium van meiose en mitose uit te putten.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>&#946;-estradiol</td>
			<td>Millipore Sigma</td>
			<td>E8875</td>
			<td>Make 1mM stocks in 95% EtOH</td>
		</tr>
		<tr>
			<td>0.22 uM Threaded Bottle-top Filter</td>
			<td>Millipore Sigma</td>
			<td>S2GPT02RE</td>
			<td></td>
		</tr>
		<tr>
			<td>100% EtOH</td>
			<td>Fisher Scientific</td>
			<td>22-032-601</td>
			<td></td>
		</tr>
		<tr>
			<td>10X PBS</td>
			<td>Fisher Scientific</td>
			<td>BP399500</td>
			<td>Dilute 1:10 to use as solvent for ConA</td>
		</tr>
		<tr>
			<td>24 mm x 50 mm coverslip No. 1.5</td>
			<td>VWR North American</td>
			<td>48393241</td>
			<td></td>
		</tr>
		<tr>
			<td>25 mm x 75 mm microscope slides</td>
			<td>VWR North American</td>
			<td>48300-026</td>
			<td></td>
		</tr>
		<tr>
			<td>Adenine hemisulfate salt</td>
			<td>Millipore Sigma</td>
			<td>A9126</td>
			<td>To supplement SC, SCA, and 1% Kac</td>
		</tr>
		<tr>
			<td>Bacto Agar</td>
			<td>BD</td>
			<td>214030</td>
			<td></td>
		</tr>
		<tr>
			<td>Concanavialin A</td>
			<td>Mllipore Sigma</td>
			<td>C2010</td>
			<td>Make as 1mg/mL in 1X PBS</td>
		</tr>
		<tr>
			<td>CoolSNAP HQ2 CCD camera</td>
			<td>Photometrics</td>
			<td></td>
			<td>Used in Section 4.3</td>
		</tr>
		<tr>
			<td>D-glucose</td>
			<td>Fisher Scientific</td>
			<td>D16-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Difco Yeast Nitrogen Base w/o Amino Acids</td>
			<td>BD</td>
			<td>291920</td>
			<td></td>
		</tr>
		<tr>
			<td>Dimethyl sulfoxide (DMSO)</td>
			<td>Millipore Sigma</td>
			<td>D5879</td>
			<td></td>
		</tr>
		<tr>
			<td>Eclipse Ti2 inverted-objective micrscope</td>
			<td>Nikon</td>
			<td></td>
			<td>Used in Section 4.4</td>
		</tr>
		<tr>
			<td>Fiji</td>
			<td>NIH</td>
			<td></td>
			<td>Download from https://fiji.sc/</td>
		</tr>
		<tr>
			<td>GE Personal DeltaVision Microscope</td>
			<td>Applied Precision</td>
			<td></td>
			<td>Used in Section 4.3</td>
		</tr>
		<tr>
			<td>L-Tryptophan&#160;</td>
			<td>Millipore Sigma</td>
			<td>T0254</td>
			<td>To supplement SC, SCA, and 1% Kac</td>
		</tr>
		<tr>
			<td>Modeling Clay</td>
			<td>Crayola</td>
			<td>&#160;2302880000</td>
			<td>To secure coverslip in slide holder</td>
		</tr>
		<tr>
			<td>NIS-Elements AR 5.30.04 Imaging Software</td>
			<td>Nikon</td>
			<td></td>
			<td>Used in Section 4.4</td>
		</tr>
		<tr>
			<td>ORCA-Fustion BT Camera</td>
			<td>Hamamatsu</td>
			<td>C15440-20UP</td>
			<td>Used in Section 4.4</td>
		</tr>
		<tr>
			<td>Plastic pipette tip holder</td>
			<td>Dot Scientific</td>
			<td>LTS1000-HR</td>
			<td>Cut a 4 square x 4 square section of the rack portion of this product.&#160;</td>
		</tr>
		<tr>
			<td>Pottassium Acetate</td>
			<td>Fisher Scientific</td>
			<td>BP264</td>
			<td></td>
		</tr>
		<tr>
			<td>Rapamycin</td>
			<td>Fisher Scientific</td>
			<td>BP29631</td>
			<td>Make 1mg/mL stocks in DMSO</td>
		</tr>
		<tr>
			<td>Silicone Sealant</td>
			<td>Aqueon</td>
			<td>100165001</td>
			<td>Also known as aquarium glue.</td>
		</tr>
		<tr>
			<td>SoftWorx7.0.0&#160; Imaging Software</td>
			<td>Applied Precision</td>
			<td></td>
			<td>Used in Section 4.3</td>
		</tr>
		<tr>
			<td>Synthetic Complete Mixture (Kaiser)&#160;</td>
			<td>Formedium</td>
			<td>DSCK2500</td>
			<td></td>
		</tr>
		<tr>
			<td>Type N immersion oil&#160;</td>
			<td>Nikon</td>
			<td>MXA22166</td>
			<td></td>
		</tr>
	</tbody>
</table>

use of time-lapse microscopy and stage-specific nuclear depletion of proteins to study meiosis in s. cerevisiae

Time-lapse fluorescentiemicroscopie heeft een revolutie teweeggebracht in het begrip van meiotische celcyclusgebeurtenissen door temporele en ruimtelijke gegevens te verstrekken die vaak niet worden gezien door het afbeelden van vaste cellen. Ontluikende gist is een belangrijk modelorganisme gebleken om meiotische chromosoomsegregatie te bestuderen, omdat veel meiotische genen sterk geconserveerd zijn. Time-lapse microscopie van meiose in ontluikende gist maakt de monitoring van verschillende meiotische mutanten mogelijk om aan te tonen hoe de mutatie meiotische processen verstoort. Veel eiwitten functioneren echter op meerdere punten bij meiose. Het gebruik van functieverlies of meiotische nulmutanten kan daarom een vroeg proces verstoren, het latere proces blokkeren of verstoren en het moeilijk maken om de fenotypen te bepalen die bij elke individuele rol horen. Om deze uitdaging te omzeilen, beschrijft dit protocol hoe de eiwitten voorwaardelijk uit de kern kunnen worden uitgeput in specifieke stadia van meiose, terwijl meiotische gebeurtenissen worden gevolgd met behulp van time-lapse-microscopie. Specifiek beschrijft dit protocol hoe de cellen worden gesynchroniseerd in profase I, hoe de anker weg techniek wordt gebruikt om eiwitten uit de kern uit te putten in specifieke meiotische stadia, en hoe time-lapse beeldvorming wordt gebruikt om meiotische chromosoomsegregatie te monitoren. Als voorbeeld van het nut van de techniek werd het kinetochore-eiwit Ctf19 op verschillende tijdstippen tijdens meiose uit de kern uitgeput en werd het aantal chromatinemassa's geanalyseerd aan het einde van meiose II. Over het algemeen kan dit protocol worden aangepast om verschillende nucleaire eiwitten uit de kern uit te putten terwijl de meiotische delingen worden bewaakt.

Om chromatinesegregatie te monitoren, werd histoneiwit Htb2 getagd met mCherry. In profase I verschijnt het chromatine als een enkele Htb2-massa. Nadat homologe chromosomen in de eerste meiotische deling zijn gescheiden, verschijnt het chromatine als twee verschillende massa's (figuur 3A). Nadat de zusterchromatiden zijn gescheiden, verschijnt het chromatine als vier massa's. Als sommige chromosomen zich niet hechten aan spindelmicrotubuli, kunnen extra massa's worden gezien na meiose I of m...

Watch this Scientific Journal Video about Use of Time-Lapse Microscopy and Stage-Specific Nuclear Depletion of Proteins to Study Meiosis in S. cerevisiae at JoVE.com

Use of Time-Lapse Microscopy and Stage-Specific Nuclear Depletion of Proteins to Study Meiosis in S. cerevisiae

Time-lapse microscopie is een waardevol hulpmiddel voor het bestuderen van meiose in ontluikende gist. Dit protocol beschrijft een methode die celcyclussynchronisatie, time-lapse-microscopie en voorwaardelijke uitputting van een doeleiwit combineert om aan te tonen hoe de functie van een specifiek eiwit tijdens meiotische chromosoomsegregatie kan worden bestudeerd.

Gebruik van time-lapse microscopie en stadiumspecifieke nucleaire uitputting van eiwitten om meiose in S. cerevisiae te bestuderen

Time-lapse fluorescence microscopy has revolutionized the understanding of meiotic cell-cycle events by providing temporal and spatial data that is often ...

Door cellen in profase één te synchroniseren en vervolgens het doeleiwit in een bepaald stadium uit te putten, kan deze methode tijdelijk verschillende functies van specifieke eiwitten identificeren. Voorwaardelijk uitputten van eiwitten in specifieke stadia van myose voorkomt de resterende effecten die een traditionele myotische mutant in latere stadia kan hebben. Deze methode kan worden gebruikt om ontluikende gistmitose en andere organismen te bestuderen die geen nucleaire enveloppe-afbraak ondergaan.Bovendien kan deze methode in andere organismen worden gebruikt om celcyclusgebeurtenissen voorafgaand aan de afbraak van de nucleaire enveloppe te bestuderen. Maak om te beginnen een agarpad dat zal worden gebruikt om een monolaag van cellen te maken voor beeldvorming. Snijd de dop af en gooi de dop en bodem een derde van een 1,5 milliliter microcentrifugebuis om een cilinder te maken die als mal voor de agarpad zal dienen.Plaats de gesneden microcentrifugebuiscilinder op een schone glazen glijbaan met de bovenkant van de buis ondersteboven, zittend op de glijbaan. Maak zes milliliter van een 5% agar-oplossing in een bekerglas van 50 milliliter. Snijd de punt van de pipet af om een grotere opening te maken en pipetteer ongeveer 500 microliter gesmolten agar in de microcentrifugebuis.Laat het op kamertemperatuur zitten totdat de agar stolt. Om gistcellen te bereiden, spint u 200 microliter van de sporulatiecultuur op 800 G gedurende twee minuten in microcentrifugebuizen van één milliliter. Gooi 180 microliter van het supernatant weg.Resuspendeer de pellet in het resterende supernatant door de buis te draaien en te bewegen. Pipetteer zes microliter van de geconcentreerde cellen op de afdekslip in het midden van de kamer ter plaatse met ConA. Houd de cilinder vast met de agarpad en schuif deze voorzichtig van de glazen schuif.Zorg ervoor dat de agar aan de onderkant volledig plat is en oefen met behulp van de onderkant van de pipetpunt een lichte hoeveelheid druk uit op de microcentrifugevorm, zodat de agarpad iets boven de grens van de buis wordt geduwd. Keer vervolgens de mal zodanig om dat het agarpad naar beneden naar de kamer is gericht. Gebruik een tang om het agar-pad voorzichtig bovenop de cellen en de pipetpunt te plaatsen om het agar-pad 10 tot 20 keer voorzichtig rond de kamer te schuiven om een monolaag van cellen op de afdekslip te creëren.Houd het agarkussen 12 tot 15 minuten in de kamer. Breng vervolgens twee milliliter sporulatiecultuur over naar twee microcentrifugebuizen en draai gedurende twee minuten op 15.700 G. Nadat u het supernatant in schone microcentrifugebuizen hebt overgebracht, draait u opnieuw in dezelfde toestand en verzamelt u het supernatant om microcentrifugebuizen te reinigen.Voeg twee milliliter van het supernatant druppelsgewijs toe aan de kamer met daarin het agarkussen. Zodra de vloeistof de bovenkant van de kamer heeft bereikt, zal de agarpad hoogstwaarschijnlijk drijven. Verwijder het agarkussen voorzichtig met een tang en gooi het weg.Plaats een afdekslip van 24 bij 50 millimeter op de bovenkant van de kamer om verdamping tijdens de beeldvorming te voorkomen. Om de film op de microscoop te plaatsen, plaatst u de afdeksel in de schuifhouder. Bevestig de vormklei aan de zijkant van de afdekslip om deze veilig in de schuifhouder te houden.Open de software voor het verkrijgen van afbeeldingen. Gebruik grove en fijne instelknoppen om de cellen scherp te stellen met behulp van DIC of helder veld. Klik in het hoofdmenu van de software voor het verwerven van afbeeldingen op Bestand, selecteer Verwerven en er verschijnen vier vensters.Klik in het venster resolve 3D op het erlenmeyerpictogram. Hiermee wordt een venster geopend met de titel Experiment uitvoeren ontwerpen, dat de besturingselementen bevat voor het instellen van een experiment om een time-lapse-film in te stellen. Ga op het tabblad Ontwerp naar het tabblad Secties.Selecteer het vakje naast Z-sectie en stel de optische sectieafstand in op één micrometer en het aantal optische secties op vijf. Klik vervolgens op het tabblad Kanalen op het pluspictogram en selecteer het juiste kanaal. Selecteer vervolgens het vakje naast Referentieafbeelding en stel de Z-positie in op het midden van het voorbeeld in het vervolgkeuzemenu.Selecteer een waarde van transmissie en belichtingstijd in het vervolgkeuzemenu. Schakel op het tabblad Time-lapse het selectievakje naast Time-lapse in en voer waarden voor minuten en uren in om het tijdsinterval van beeldacquisitie te identificeren. Schakel het selectievakje naast Focus behouden met ultieme focus in om fasedrift tijdens de film te voorkomen.En selecteer op het tabblad Punten het vakje naast Lijst met toegangspunten bezoeken. Klik in het hoofdmenu op Beeld en selecteer Puntenlijst. Verplaats het werkgebied naar een gebied van de kamer dat een monolaag van cellen toont.Klik op Punt markeren in het venster Puntenlijst. Verplaats het werkgebied om 25 tot 30 punten te selecteren zonder enige overlap om te voorkomen dat de cellen overbelichten en elk veld tijdens elke tijdcursus afbeeldt. Selecteer in het venster Puntenlijst de optie Alles kalibreren om de uiteindelijke focus voor elk punt in te stellen.Sla het bestand op het tabblad Uitvoeren op de juiste bestemming op de computer op. Selecteer in het venster Experiment uitvoeren de knop Afspelen om de film te starten. Open de Fiji-software.Open de kanalen DIC en mCherry. Verkrijg een enkele maximale intensiteitsprojectie van het mCherry-kanaal door op Afbeelding te klikken, gevolgd door Stacks en Z Project en selecteer Maximale intensiteit in het vervolgkeuzemenu. Als u de DIC- en mCherry-kanalen in één afbeelding wilt samenvoegen, klikt u op Afbeelding, Kleur en selecteert u Kanalen samenvoegen.Volg een enkele cel door meiose. Noteer na de voltooiing van meiose II het aantal DNA-massa's. In wildtype cellen met de ankerachtergrond zijn er meestal vier DNA-massa's aan het einde van meiose II, die de vier producten van meiose vertegenwoordigen.In een klein deel van de cellen zijn slechts drie massa's zichtbaar na meiose II.Wanneer Ctf19-FRB is verankerd op het moment van afgifte van profase I, vertoont ongeveer 47% van de cellen meer dan vier DNA-massa's na voltooiing van meiose, wat wijst op een defect in de aanhechting van kinetochoren en microtubuli. Met verankering van Ctf19-FRB, hetzij na kinetochore assemblage maar vóór meiose I, of na meiose II, vertoont ongeveer 16% van de cellen extra DNA-massa's. Een van de belangrijkste onderdelen van dit protocol is om het supernatant druppelsgewijs aan je kamer toe te voegen om te voorkomen dat je monolaag wordt verstoord.Noteer bovendien de tijd die nodig is om u voor te bereiden op beeldvorming om het in uw analyse te overwegen. Door fluorescerend verpakte eiwitten te veranderen, kan deze procedure worden gebruikt om de vragen te beantwoorden over de duur van de celcyclus, chromosoomsegregatie, eiwitrijkdom en eiwitlokalisatie.

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JoVE Journal

Biology

Use of Time-Lapse Microscopy and Stage-Specific Nuclear Depletion of Proteins to Study Meiosis in S. cerevisiae

Assay for Adhesion and Agar Invasion in S. cerevisiae

Yeasts are found in natural biofilms, where many microorganisms colonize surfaces. In artificial environments, such as surfaces of man-made objects, biofilms can reduce industrial productivity, destroy structures, and threaten human life. 1-3 On the other hand, harnessing the power of biofilms can help clean the environment and generate sustainable energy. 4-8
The ability of S. cerevisiae to colonize surfaces and participate in complex biofilms was mostly ignored until the rediscovery of the differentiation programs triggered by various signaling pathways and environmental cues in this organism. 9, 10 The continuing interest in using S. cerevisiae as a model organism to understand the interaction and convergence of signaling pathways, such as the Ras-PKA, Kss1 MAPK, and Hog1 osmolarity pathways, quickly placed S. cerevisiae in the junction of biofilm biology and signal transduction research. 11-20 To this end, differentiation of yeast cells into long, adhesive, pseudohyphal filaments became a convenient readout for the activation of signal transduction pathways upon various environmental changes. However, filamentation is a complex collection of phenotypes, which makes assaying for it as if it were a simple phenotype misleading. In the past decade, several assays were successfully adopted from bacterial biofilm studies to yeast research, such as MAT formation assays to measure colony spread on soft agar and crystal violet staining to quantitatively measure cell-surface adherence. 12, 21 However, there has been some confusion in assays developed to qualitatively assess the adhesive and invasive phenotypes of yeast in agar.
Here, we present a simple and reliable method for assessing the adhesive and invasive quality of yeast strains with easy-to-understand steps to isolate the adhesion assessment from invasion assessment. Our method, adopted from previous studies, 10, 16 involves growing cells in liquid media and plating on differential nutrient conditions for growth of large spots, which we then wash with water to assess adhesion and rub cells completely off the agar surface to assess invasion into the agar. We eliminate the need for streaking cells onto agar, which affects the invasion of cells into the agar. In general, we observed that haploid strains that invade agar are always adhesive, yet not all adhesive strains can invade agar medium. Our approach can be used in conjunction with other assays to carefully dissect the differentiation steps and requirements of yeast signal transduction, differentiation, quorum sensing, and biofilm formation.

We describe a qualitative assay for yeast adhesion and agar invasion as a measure of invasive and pseudohyphal differentiation. This simple assay can be used to assess the invasive phenotype of various mutants as well as the effects environmental cues and signaling pathways on yeast differentiation.

Test voor Adhesie en Agar invasie in S. cerevisiae

Yeasts are found in natural biofilms, where many microorganisms colonize surfaces. In artificial environments, such as surfaces of man-made objects, ...

Monitoring Actin Disassembly with Time-lapse Microscopy

Monitoring Actin Demontage met Time-lapse Microscopie

Two-photon axotomy and time-lapse confocal imaging in live zebrafish embryos

Zebrafish have long been utilized to study the cellular and molecular mechanisms of development by time-lapse imaging of the living transparent embryo. Here we describe a method to mount zebrafish embryos for long-term imaging and demonstrate how to automate the capture of time-lapse images using a confocal microscope. We also describe a method to create controlled, precise damage to individual branches of peripheral sensory axons in zebrafish using the focused power of a femtosecond laser mounted on a two-photon microscope. The parameters for successful two-photon axotomy must be optimized for each microscope. We will demonstrate two-photon axotomy on both a custom built two-photon microscope and a Zeiss 510 confocal/two-photon to provide two examples.

Zebrafish trigeminal sensory neurons can be visualized in a transgenic line expressing GFP driven by a sensory neuron specific promoter 1. We have adapted this zebrafish trigeminal model to directly observe sensory axon regeneration in living zebrafish embryos. Embryos are anesthetized with tricaine and positioned within a drop of agarose as it solidifies. Immobilized embryos are sealed within an imaging chamber filled with phenylthiourea (PTU) Ringers. We have found that embryos can be continuously imaged in these chambers for 12-48 hours. A single confocal image is then captured to determine the desired site of axotomy. The region of interest is located on the two-photon microscope by imaging the sensory axons under low, non-damaging power. After zooming in on the desired site of axotomy, the power is increased and a single scan of that defined region is sufficient to sever the axon. Multiple location time-lapse imaging is then set up on a confocal microscope to directly observe axonal recovery from injury.

Here we describe a method for mounting zebrafish embryos for long-term imaging, two-photon imaging and tissue-damage techniques, and time-lapse confocal imaging.

Twee-foton axotomy en time-lapse confocale imaging in levende zebravis embryo&#39;s

Zebrafish have long been utilized to study the cellular and molecular mechanisms of development by time-lapse imaging of the living transparent embryo.  ...

A high-throughput method to globally study the organelle morphology in S. cerevisiae

High-throughput methods to examine protein localization or organelle morphology is an effective tool for studying protein interactions and can help achieve an comprehensive understanding of molecular pathways. In Saccharomyces cerevisiae, with the development of the non-essential gene deletion array, we can globally study the morphology of different organelles like the endoplasmic reticulum (ER) and the mitochondria using GFP (or variant)-markers in different gene backgrounds. However, incorporating GFP markers in each single mutant individually is a labor-intensive process. Here, we describe a procedure that is routinely used in our laboratory. By using a robotic system to handle high-density yeast arrays and drug selection techniques, we can significantly shorten the time required and improve reproducibility. In brief, we cross a GFP-tagged mitochondrial marker (Apc1-GFP) to a high-density array of 4,672 nonessential gene deletion mutants by robotic replica pinning.  Through diploid selection, sporulation, germination and dual marker selection, we recover both alleles. As a result, each haploid single mutant contains Apc1-GFP incorporated at its genomic locus. Now, we can study the morphology of mitochondria in all non-essential mutant background. Using this high-throughput approach, we can conveniently study and delineate the pathways and genes involved in the inheritance and the formation of organelles in a genome-wide setting.

GFP-fusion proteins are widely used to visualize organelles by confocal microscopy. However, screening for mutations that affect the morphology of organelles generally requires individual mutagenesis and is time consuming. Here, we demonstrate a method to simultaneously incorporate organelle-GFP markers in almost 5,000 non-essential genes in yeast.

Een high-throughput methode om wereldwijd de studie van de morfologie organel in S. cerevisiae

High-throughput methods to examine protein localization or organelle morphology is an effective tool for studying protein interactions and can help ...

Identification of protein complexes with quantitative proteomics in S. cerevisiae

Lipids are the building blocks of cellular membranes that function as barriers and in compartmentalization of cellular processes, and recently, as important intracellular signalling molecules. However, unlike proteins, lipids are small hydrophobic molecules that traffic primarily by poorly described nonvesicular routes, which are hypothesized to occur at membrane contact sites (MCSs). MCSs are regions where the endoplasmic reticulum (ER) makes direct physical contact with a partnering organelle, e.g., plasma membrane (PM). The ER portion of ER-PM MCSs is enriched in lipid-synthesizing enzymes, suggesting that lipid synthesis is directed to these sites and implying that MCSs are important for lipid traffic. Yeast is an ideal model to study ER-PM MCSs because of their abundance, with over 1000 contacts per cell, and their conserved nature in all eukaryotes. Uncovering the proteins that constitute MCSs is critical to understanding how lipids traffic is accomplished in cells, and how they act as signaling molecules. We have found that an ER called Scs2p localize to ER-PM MCSs and is important for their formation. We are focused on uncovering the molecular partners of Scs2p. Identification of protein complexes traditionally relies on first resolving purified protein samples by gel electrophoresis, followed by in-gel digestion of protein bands and analysis of peptides by mass spectrometry. This often limits the study to a small subset of proteins. Also, protein complexes are exposed to denaturing or non-physiological conditions during the procedure. To circumvent these problems, we have implemented a large-scale quantitative proteomics technique to extract unbiased and quantified data. We use stable isotope labeling with amino acids in cell culture (SILAC) to incorporate staple isotope nuclei in proteins in an untagged control strain. Equal volumes of tagged culture and untagged, SILAC-labeled culture are mixed together and lysed by grinding in liquid nitrogen. We then carry out an affinity purification procedure to pull down protein complexes. Finally, we precipitate the protein sample, which is ready for analysis by high-performance liquid chromatography/ tandem mass spectrometry. Most importantly, proteins in the control strain are labeled by the heavy isotope and will produce a mass/ charge shift that can be quantified against the unlabeled proteins in the bait strain. Therefore, contaminants, or unspecific binding can be easily eliminated. By using this approach, we have identified several novel proteins that localize to ER-PM MCSs. Here we present a detailed description of our approach. 

Here we describe a new quantitative proteomics technique for identifying protein complexes in Saccharomyces cerevisiae. In this study, we have used the SILAC method together with affinity purification followed by tandem mass spectrometry to identify with high specificity the binding partners of an ER protein, Scs2p.

Identificatie van eiwit-complexen met kwantitatieve proteomics in S. cerevisiae

Lipids are the building blocks of cellular membranes that function as barriers and in compartmentalization of cellular processes, and recently, as ...

Time-lapse Imaging of Mitosis After siRNA Transfection

Changes in cellular organization and chromosome dynamics that occur during mitosis are tightly coordinated to ensure accurate inheritance of genomic and cellular content. Hallmark events of mitosis, such as chromosome movement, can be readily tracked on an individual cell basis using time-lapse fluorescence microscopy of mammalian cell lines expressing specific GFP-tagged proteins. In combination with RNAi-based depletion, this can be a powerful method for pinpointing the stage(s) of mitosis where defects occur after levels of a particular protein have been lowered. In this protocol, we present a basic method for assessing the effect of depleting a potential mitotic regulatory protein on the timing of mitosis. Cells are transfected with siRNA, placed in a stage-top incubation chamber, and imaged using an automated fluorescence microscope. We describe how to use software to set up a time-lapse experiment, how to process the image sequences to make either still-image montages or movies, and how to quantify and analyze the timing of mitotic stages using a cell-line expressing mCherry-tagged histone H2B. Finally, we discuss important considerations for designing a time-lapse experiment. This strategy is complementary to other approaches and offers the advantages of 1) sensitivity to changes in kinetics that might not be observed when looking at cells as a population and 2) analysis of mitosis without the need to synchronize the cell cycle using drug treatments. The visual information from such imaging experiments not only allows the sub-stages of mitosis to be assessed, but can also provide unexpected insight that would not be apparent from cell cycle analysis by FACS.

Here we describe a basic protocol to image and quantify the mitotic timing of live mammalian tissue culture cells after siRNA transfection.

Time-lapse Imaging van mitose Na siRNA transfectie

Changes in cellular organization and chromosome dynamics that occur during mitosis are tightly coordinated to ensure accurate inheritance of genomic and ...

Time-lapse Microscopy of Early Embryogenesis in Caenorhabditis elegans

Caenorhabditis elegans has often been used as a model system in studies of early developmental processes. The transparency of the 
embryos, the genetic resources, and the relative ease of transformation are qualities that make C. elegans an excellent model for early embryogenesis. Laser-based 
confocal microscopy and fluorescently labeled tags allow researchers to follow specific cellular structures and proteins in the developing embryo. For example, 
one can follow specific organelles, such as lysosomes or mitochondria, using fluorescently labeled dyes. These dyes can be delivered to the early embryo by means 
of microinjection into the adult gonad. Also, the localization of specific proteins can be followed using fluorescent protein tags. Examples are presented here 
demonstrating the use of a fluorescent lysosomal dye as well as fluorescently tagged histone and ubiquitin proteins. The labeled histone is used to visualize 
the DNA and thus identify the stage of the cell cycle. GFP-tagged ubiquitin reveals the dynamics of ubiquitinated vesicles in the early embryo. Observations 
of labeled lysosomes and GFP:: ubiquitin can be used to determine if there is colocalization between ubiquitinated vesicles and lysosomes. A technique for 
the microinjection of the lysosomal dye is presented. Techniques for generating transgenenic strains are presented elsewhere (1, 2). For imaging, embryos 
are cut out of adult hermaphrodite nematodes and mounted onto 2% agarose pads followed by time-lapse microscopy on a standard laser scanning confocal 
microscope or a spinning disk confocal microscope. This methodology provides for the high resolution visualization of early embryogenesis.

Time-lapse Microscopy of Early Embryogenesis in Caenorhabditis elegans

This article describes a technique for the visualization of the early events of embryogenesis in the nematode Caenorhabditis elegans.

Time-lapse microscopie van de vroege embryogenese in Caenorhabditis elegans

Caenorhabditis elegans has often been used as a model system in studies of early developmental processes.  The transparency of the 
embryos, the genetic ...

Quantitative Analysis of Random Migration of Cells Using Time-lapse Video Microscopy

Cell migration is a dynamic process, which is important for embryonic development, tissue repair, immune system function, and tumor invasion 1, 2. During directional migration, cells move rapidly in response to an extracellular chemotactic signal, or in response to intrinsic cues 3 provided by the basic motility machinery. Random migration occurs when a cell possesses low intrinsic directionality, allowing the cells to explore their local environment.
Cell migration is a complex process, in the initial response cell undergoes polarization and extends protrusions in the direction of migration 2. Traditional methods to measure migration such as the Boyden chamber migration assay is an easy method to measure chemotaxis in vitro, which allows measuring migration as an end point result. However, this approach neither allows measurement of individual migration parameters, nor does it allow to visualization of morphological changes that cell undergoes during migration.
Here, we present a method that allows us to monitor migrating cells in real time using video - time lapse microscopy. Since cell migration and invasion are hallmarks of cancer, this method will be applicable in studying cancer cell migration and invasion in vitro. Random migration of platelets has been considered as one of the parameters of platelet function 4, hence this method could also be helpful in studying platelet functions. This assay has the advantage of being rapid, reliable, reproducible, and does not require optimization of cell numbers. In order to maintain physiologically suitable conditions for cells, the microscope is equipped with CO2 supply and temperature thermostat. Cell movement is monitored by taking pictures using a camera fitted to the microscope at regular intervals. Cell migration can be calculated by measuring average speed and average displacement, which is calculated by Slidebook software.

This method allows monitoring of cells in real time and quantitative measurements of different cell migration parameters such as speed, displacement, and velocity. Unlike the traditional methods, this real time approach is not based on endpoint quantitative migration measurements; instead it allows monitoring and calculating different parameters continuously.

Kwantitatieve analyse van Random migratie van cellen met behulp van time-lapse video Microscopie

Cell migration is a dynamic process, which is important for embryonic development, tissue repair, immune system function, and tumor invasion 1, 2. During ...

Flow Cytometry-based Purification of S. cerevisiae Zygotes

Zygotes are essential intermediates between haploid and diploid states in the life cycle of many organisms, including yeast (Figure 1) 1. S. cerevisiae zygotes result from the fusion of haploid cells of distinct mating type (MATa, MATalpha) and give rise to corresponding stable diploids that successively generate as many as 20 diploid progeny as a result of their strikingly asymmetric mitotic divisions 2. Zygote formation is orchestrated by a complex sequence of events: In this process, soluble mating factors bind to cognate receptors, triggering receptor-mediated signaling cascades that facilitate interruption of the cell cycle and culminate in cell-cell fusion. Zygotes may be considered a model for progenitor or stem cell function.
Although much has been learned about the formation of zygotes and although zygotes have been used to investigate cell-molecular questions of general significance, almost all studies have made use of mating mixtures in which zygotes are intermixed with a majority population of haploid cells 3-8. Many aspects of the biochemistry of zygote formation and the continuing life of the zygote therefore remain uninvestigated.
Reports of purification of yeast zygotes describe protocols based on their sedimentation properties 9; however, this sedimentation-based procedure did not yield nearly 90% purity in our hands. Moreover, it has the disadvantage that cells are exposed to hypertonic sorbitol. We therefore have developed a versatile purification procedure. For this purpose, pairs of haploid cells expressing red or green fluorescent proteins were co-incubated to allow zygote formation, harvested at various times, and the resulting zygotes were purified using a flow cytometry-based sorting protocol. This technique provides a convenient visual assessment of purity and maturation. The average purity of the fraction is approximately 90%. According to the timing of harvest, zygotes of varying degrees of maturity can be recovered. The purified samples provide a convenient point of departure for "-omic" studies, for recovery of initial progeny, and for systematic investigation of this progenitor cell.

Flow Cytometry-based Purification of S. cerevisiae Zygotes

To purify zygotes of S. cerevisiae, haploid cells of opposite mating type were engineered to express red or green fluorescent proteins, co-incubated to allow zygote formation, and fractionated using a flow cytometry-based protocol. The highly-enriched fraction enables subsequent "-omic" studies, recovery of initial progeny, and systematic investigation of zygote morphogenesis.

Flowcytometrie gebaseerde Zuivering van<em&gt; S. cerevisiae</em&gt; Zygoten

Zygotes are essential intermediates between haploid and diploid states in the life cycle of many organisms, including yeast (Figure 1) 1. S. cerevisiae ...

Use of Time Lapse Microscopy to Visualize Anoxia-induced Suspended Animation in C. elegans Embryos

Caenorhabdits elegans has been used extensively in the study of stress resistance, which is facilitated by the transparency of the adult and embryo stages as well as by the availability of genetic mutants and transgenic strains expressing a myriad of fusion proteins1-4. In addition, dynamic processes such as cell division can be viewed using fluorescently labeled reporter proteins. The study of mitosis can be facilitated through the use of time-lapse experiments in various systems including intact organisms; thus the early C. elegans embryo is well suited for this study. Presented here is a technique by which in vivo imaging of sub-cellular structures in response to anoxic (99.999% N2; &lt;2 ppm O2) stress is possible using a simple gas flow through setup on a high-powered microscope. A microincubation chamber is used in conjunction with nitrogen gas flow through and a spinning disc confocal microscope to create a controlled environment in which animals can be imaged in vivo. Using GFP-tagged gamma tubulin and histone, the dynamics and arrest of cell division can be monitored before, during and after exposure to an oxygen-deprived environment. The results of this technique are high resolution, detailed videos and images of cellular structures within blastomeres of embryos exposed to oxygen deprivation.

Use of Time Lapse Microscopy to Visualize Anoxia-induced Suspended Animation in C. elegans Embryos

Described here is an in vivo technique to image sub-cellular structures in animals exposed to anoxia using a gas flow through microincubation chamber in conjunction with a spinning disc confocal microscope. This method is straightforward and flexible enough to suit a variety of experimental parameters and model systems.

Het gebruik van Time lapse microscopie om Anoxie-geïnduceerde Suspended Animation Visualiseer in<em&gt; C. elegans</em&gt; Embryo&#39;s

Caenorhabdits elegans has been used extensively in the study of stress resistance, which is facilitated by the transparency of the adult and embryo stages ...