Name: Efficient Sporulation of Saccharomyces cerevisiae in a 96 Multiwell Format (Video) | JoVE Journal
Uploaded: 2016-09-17T14:00:00.000+00:00
Duration: 8 min 54 s
Description: Learn efficient sporulation of Saccharomyces cerevisiae in a 96-well format for high-throughput genetic screening. This optimized aeration method enables cost-effective yeast mutant analysis and plasmid library studies.

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5 minutes

This work was supported by a Joseph P. Healey grant from the University of Massachusetts Boston (L.S.H.) and R15 GM86805 from the NIH (L.S.H.). S.M.P. is supported in part by a Sanofi-Genzyme Fellowship at the University of Massachusetts Boston.

1. Preparing for Sporulation
Note: The media described in this protocol are made using standard recipes and methods13,17. Table 1 gives the formulation for 1 L of the various media used in this protocol.
<table border="1" cellpadding="0" cellspacing="0" height="180" width="469">
	<colgroup>
		<col />
		<col />
		<col span="3" />
		<col />
		<col span="2" />
	</colgroup>
	<tbody>
		<tr height="15">
			<td height="15" style="height:20px;"></td>
			<td style="width: 55px;">Bacto Peptone</td>
			<td style="width: 50px;">Yeast Extract</td>
			<td style="width: 50px;">Bacto Agar</td>
			<td style="width: 60px;">Dextrose</td>
			<td style="width: 70px;">Potassium Acetate</td>
			<td style="width: 60px;">Glycerol</td>
			<td style="width: 60px;">ddH2O</td>
		</tr>
		<tr height="15">
			<td height="15" style="height:20px;">YPG plates</td>
			<td>20 g</td>
			<td>10 g</td>
			<td>20 g</td>
			<td>-</td>
			<td>-</td>
			<td>30 ml</td>
			<td>970 ml</td>
		</tr>
		<tr height="15">
			<td height="15" style="height:20px;">YPD plates</td>
			<td>20 g</td>
			<td>10 g</td>
			<td>20 g</td>
			<td>20 g</td>
			<td>-</td>
			<td>-</td>
			<td>1,000 ml</td>
		</tr>
		<tr height="15">
			<td height="15" style="height:20px;">YPD liquid</td>
			<td>20 g</td>
			<td>10 g</td>
			<td>-</td>
			<td>20 g</td>
			<td>-</td>
			<td>-</td>
			<td>1,000 ml</td>
		</tr>
		<tr height="15">
			<td height="15" style="height:20px;">YPA liquid</td>
			<td>20 g</td>
			<td>10 g</td>
			<td>-</td>
			<td>-</td>
			<td>20 g</td>
			<td>-</td>
			<td>1,000 ml</td>
		</tr>
		<tr height="15">
			<td style="height: 20px; width: 80px;">Sporulation media</td>
			<td>-</td>
			<td>-</td>
			<td>-</td>
			<td>-</td>
			<td>10 g</td>
			<td>-</td>
			<td>1,000 ml</td>
		</tr>
	</tbody>
</table>
Table 1: Media formulations. Amounts are given for 1 L of media. Specifics about media ingredients can be found in the Materials Table.
<ol>
	<li>If All Sporulating Cells will be the Same Genotype, Follow This Procedure:
	<ol>
		<li>Thaw yeast strain to be used onto a YPG (YPGlycerol) plate. Grow yeast for 12-16 hr at 30 &#176;C. Importantly, SK1 cells are also poised to sporulate, so SK1 strains should not be left too long on YPG plates, or they may sporulate on the plate. 
		Note: A freshly thawed strain grown on YPG is preferred, as utilization of glycerol as a carbon source requires oxidative phosphorylation, and thus selects for cells that have functional mitochondrial DNA. SK1 cells have a tendency to lose functional mitochondrial DNA and become petites. Functional mitochondrial DNA is needed for sporulation.</li>
		<li>Streak yeast from the YPG plate onto a YPD (YPDextrose) plate for single colonies. Grow yeast on YPD plate 24-28 hr at 30 &#176;C.</li>
		<li>After about 36-48 hr of growth on YPD solid media, start a 25 ml YPD culture using a single colony from the YPD plate. Grow this culture until cells are about OD600 = 4.0 to 7.0. Perform this step at 30 &#176;C overnight in a shaking incubator, shaking at 220 rpm.</li>
		<li>From the YPD culture, use an appropriate amount of cells to start 1,000 ml of YPA (YPAcetate) culture that is OD600 = 0.1 for each 96 well plate need in Section 2. Grow yeast in a 30 &#176;C shaking incubator (shaking at 220 rpm) until the culture OD600 is between 1.3 to 1.5. 
		Note: Inoculate 100 ml of YPA culture for each 96 multiwell plate to be screened in Section 2. For example, if screening four 96 multiwell plates, 400 ml of YPA culture will be needed. Starting with 10% extra volume in the YPA culture is necessary to protect against evaporative volume loss. Typically, it will take between 12-16 hr for cells to reach the appropriate OD600; the amount of time may vary depending on the genotype of the yeast strain. YPA is the presporulation media. Pregrowth in acetate helps induce expression of genes (such as IME1) needed for efficient and synchronous sporulation6.</li>
		<li>Spin at 1,800 x g in a table top centrifuge for 5 min to pellet cells grown in YPA. Wash cells 1x with 0.5 volume of sterile autoclaved deionized water. Spin again, and discard wash. Resuspend cells in 1x volume sporulation media. Continue to Section 2.</li>
	</ol>
	</li>
	<li>If using cells for sporulation that are of different genotypes, (i.e., transformed with different plasmids or containing different mutations, typically obtained and stored as frozen stocks), array cells of the different genotypes into a 96 multiwell format. Then, follow this procedure:
	<ol>
		<li>Use a sterile 96 prong frogger to transfer cells from thawed frozen stocks in 96 multiwell plate(s) onto YPG solid media. Grow yeast overnight at 30 &#176;C.</li>
		<li>Using a sterile 96 prong frogger, transfer cells from YPG solid media onto YPD solid media or selective solid media (i.e., synthetic minimal media lacking amino acids, if the cells contain plasmids that require selection). Grow yeast at 30 &#176;C until colonies are formed for each strain, typically 1 day on YPD and 2 days if selective media is necessary.</li>
		<li>Aliquot 1.2 ml of YPD liquid media or selective liquid media into each well of a 96 deep 2 ml multiwell plate. Transfer cells from solid media into liquid media using a frogger, cover with a plastic lid held in place by tape, and grow overnight in 30 &#176;C shaker, shaking at 220 rpm. 
		Note: To minimize contamination, cover plates using the plastic lids from a rectangular petri plate. Hold lids in place using a piece of tape, so that air circulation is minimally restricted.</li>
		<li>Centrifuge plates at 1,800 x g for 5 min, using a swinging bucket centrifuge with adaptors to accommodate 96 well plates. Pour off media from cells; add 500 &#181;l YPA to each well and resuspend pelleted cells in the YPA. Cover with plastic lid held in place by tape.</li>
		<li>Grow cells for 15 hr at 30 &#176;C in a shaking incubator, shaking at 220 rpm. Continue to Section 2.</li>
	</ol>
	</li>
</ol>
2. Sporulating Cells in a 96 Multiwell Format
<ol>
	<li>Add either one 3 mm sterile solid glass bead or a sterile 5 mm x 2 mm magnetic stir bar into each well of a 96 well plate with 1.3 ml wells. (See Representative Results below for a discussion on whether to use a bead or a stir bar.)</li>
	<li>If all cells to be screened are of the same genotype, go to 2.2.1. If cells to be screened are of different genotypes, go to 2.2.2.
	<ol>
		<li>Take cells from step 1.1.5 and aliquot 500 &#181;l of cells plus media into each well of the 96 multiwell plate. Cover with plastic lid held in place by tape. Proceed to 2.3.</li>
		<li>Spin cells that are in YPA from 1.2.4 at 1,800 x g for 5 min, using a swinging bucket centrifuge with adaptors to accommodate 96 well plates. Pour off media from cells. Add 500 &#181;l of sporulation media to each well and resuspend pelleted cells in the sporulation media. Cover with plastic lid held in place by tape. Proceed to 2.3.</li>
	</ol>
	</li>
	<li>If using a glass bead, place samples in a shaking incubator at 30&#176; C and shake at 220 rpm for sporulation. If using a magnetic stir bar, place samples on a stir plate inside of a 30 &#176;C incubator for sporulation. 
	Note: The exact stir speed for the magnetic stir bars is not very important, as long as all bars are moving energetically and the culture is aerated.</li>
	<li>To monitor progression through sporulation, withdraw samples from the sporulating culture for visualization, Add 6 &#181;l of cells from the sporulating cultures to 24 &#181;l of sporulation media in a 96 well coverslip plate (1:5 dilution). Leave cells to settle for 5 min before examining cells using an inverted microscope. 
	Note: In wild type SK1 cells, compact mature spores will form by 36 hours after transfer to sporulation media. Progression through sporulation can be monitored by microscopy using fluorescent markers, such as a nuclear marker (i.e., Htb2-mCherry18) to examine the meiotic division or a prospore membrane marker (i.e., G2019) to examine spore morphogenesis. Alternatively, the formation of refractile spores can be seen using Nomarski DIC microscopy starting about 12 hr after transfer to sporulation media.</li>
</ol>

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<li>Neiman, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Sporulation+in+the+budding+yeast+Saccharomyces+cerevisiae%5BTitle%5D)+AND+%22Genetics%22%5BJournal%5D)">Sporulation in the budding yeast Saccharomyces cerevisiae.</a> Genetics. 189 (3), 737-765 (2011).</li>
<li>Padmore, R., Cao, L., Kleckner, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Temporal+comparison+of+recombination+and+synaptonemal+complex+formation+during+meiosis+in+S.+cerevisiae%5BTitle%5D)+AND+%22Cell%22%5BJournal%5D)">Temporal comparison of recombination and synaptonemal complex formation during meiosis in S. cerevisiae.</a> Cell. 66 (6), 1239-1256 (1991).</li>
<li>Liti, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Population+genomics+of+domestic+and+wild+yeasts%5BTitle%5D)+AND+%22Nature%22%5BJournal%5D)">Population genomics of domestic and wild yeasts.</a> Nature. 458 (7236), 337-341 (2009).</li>
<li>McCusker, J. H., Haber, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Efficient+sporulation+of+yeast+in+media+buffered+near+pH6%5BTitle%5D)+AND+%22J.+Bacteriol%22%5BJournal%5D)">Efficient sporulation of yeast in media buffered near pH6.</a> J. Bacteriol. 132 (1), 180-185 (1977).</li>
<li>Codon, A. C., Gasent-Ramirez, J. M., Benitez, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Factors+which+affect+the+frequency+of+sporulation+and+tetrad+formation+in+Saccharomyces+cerevisiae+baker%27s+yeasts%5BTitle%5D)+AND+%22Appl.+Environ.+Microbiol%22%5BJournal%5D)">Factors which affect the frequency of sporulation and tetrad formation in Saccharomyces cerevisiae baker's yeasts.</a> Appl. Environ. Microbiol. 61 (2), 630-638 (1995).</li>
<li>Elrod, S. L., Chen, S. M., Schwartz, K., Shuster, E. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Optimizing+sporulation+conditions+for+different+Saccharomyces+cerevisiae+strain+backgrounds%5BTitle%5D)+AND+%22Methods+Mol.+Biol%22%5BJournal%5D)">Optimizing sporulation conditions for different Saccharomyces cerevisiae strain backgrounds.</a> Methods Mol. Biol. 557, 21-26 (2009).</li>
<li>Börner, G. V., Cha, R. S. Analysis of yeast sporulation efficiency, spore viability, and meiotic recombination on solid medium. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aB%C3%B6rner%2C+GV+%22Cold+Spring+Harb.+Protoc%22">Cold Spring Harb. Protoc</a>. 2015 (11), 1003-1008 (2015).</li>
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<li>Jones, G. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+systematic+library+for+comprehensive+overexpression+screens+in+Saccharomyces+cerevisiae%5BTitle%5D)+AND+%22Nat.+Methods%22%5BJournal%5D)">A systematic library for comprehensive overexpression screens in Saccharomyces cerevisiae.</a> Nat. Methods. 5 (3), 239-241 (2008).</li>
<li>Fleming, M. S., Gitler, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((High-throughput+yeast+plasmid+overexpession+screen%5BTitle%5D)+AND+%22J.+Vis.+Exp%22%5BJournal%5D)">High-throughput yeast plasmid overexpession screen.</a> J. Vis. Exp. (53), e2836(2011).</li>
<li>Paulissen, S. M., Slubowski, C. J., Roesner, J. M., Huang, L. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Timely+Closure+of+the+Prospore+Membrane+Requires+SPS1+and+SPO77+in+Saccharomyces+cerevisiae%5BTitle%5D)+AND+%22Genetics%22%5BJournal%5D)">Timely Closure of the Prospore Membrane Requires SPS1 and SPO77 in Saccharomyces cerevisiae.</a> Genetics. , (2016).</li>
<li>Amberg, D. C., Burke, D., Strathern, J. N. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aAmberg%2C+DC+%22Methods+in+Yeast+Genetics%3A+A+Cold+Spring+Harbor+Labooratory+Manual%22">Methods in Yeast Genetics: A Cold Spring Harbor Labooratory Manual</a>. , Cold Spring Harbor Laboratory Press. Cold Spring, NY. (2005).</li>
<li>Parodi, E. M., Baker, C. S., Tetzlaff, C., Villahermosa, S., Huang, L. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((SPO71+mediates+prospore+membrane+size+and+maturation+in+Saccharomyces+cerevisiae%5BTitle%5D)+AND+%22Eukaryot.+Cell%22%5BJournal%5D)">SPO71 mediates prospore membrane size and maturation in Saccharomyces cerevisiae.</a> Eukaryot. Cell. 11 (10), 1191-1200 (2012).</li>
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The authors have no competing financial interests.

Here we present a protocol for sporulating SK1 yeast in a 96 multiwell format. Aeration is key for efficient sporulation, which requires the use of either a stir bar or a glass bead in each well. When cells are sporulated in a 96 multiwell plate in a shaking incubator without either a bead or a stir bar, cells do not sporulate efficiently. Only a small increase in sporulation efficiency is seen when cells are sporulated without either a bead or a stir bar in a shaking incubator, compared to being at 30 &#176;C without ag...

Sporulation in the budding yeast has been studied to provide insights into many aspects of biology, including the control of chromosome segregation during meiosis1, mechanisms of genetic recombination2, the control of development by cell signaling3, nutritional control of development4, the transcriptional regulation of development5, and the examination of spore formation6. Spore formation includes a novel cell division event involving the formation of new membrane compartments within the mother cell followed by the deposition of a protective spore wall6. These studies that examine sporulating cells often take advantage of the rapidly sporulating yeast strain SK1, which can undergo the process of sporulation in about 24 hr in a relatively efficient fashion7,8. Although optimization of sporulation conditions for budding yeast have been described9-13, these experiments examined sporulation on solid media or in larger scale liquid cultures where sporulation is carried out using culture tubes or flasks.
Here we describe a method for sporulating yeast in a 96 multiwell plate format. We find that for this method, aeration is critical for synchronous and efficient sporulation, and have devised techniques to ensure sufficient sporulation a small-volume multiwell format. Sporulating in a 96 multiwell plate format allows for cells to be screened using high-throughput techniques and reagents optimized for a multiwell plate format, such screening for high copy suppressors using a tiled library14-16.

<table><tbody><tr><td>Nunc 1.3 ml DeepWell Plates</td><td>ThermoScientific</td><td>260251</td><td>Used for sporulation</td></tr><tr><td>Nunc 2.0 ml DeepWell plates</td><td>ThermoScientific</td><td>278743</td><td>Used for presporulation growth, step 1.2.3</td></tr><tr><td>3 mm glass bead</td><td>Fisher</td><td>11-312A</td><td>Used for sporulation</td></tr><tr><td>5 mm x 2 mm stir bar, pack of 12</td><td>Fisher</td><td>14-511-82</td><td>Used for sporulation</td></tr><tr><td>96 well frogger</td><td>V&amp;amp;P Scientific</td><td>VP407</td><td>needed for step 1.2</td></tr><tr><td>library copier</td><td>V&amp;amp;P Scientific</td><td>VP381</td><td>needed for step 1.2; to be used with the frogger</td></tr><tr><td>rectangular Petri dish</td><td>ThermoScientific</td><td>264728</td><td>needed for step 1.2</td></tr><tr><td>Bacto Peptone</td><td>BD</td><td>211677</td><td>needed for media</td></tr><tr><td>Yeast Extract</td><td>BD</td><td>212750</td><td>needed for media</td></tr><tr><td>Bacto Agar</td><td>BD</td><td>212750</td><td>needed for media</td></tr><tr><td>Dextrose</td><td>Fisher</td><td>D16-3</td><td>needed for media</td></tr><tr><td>Potassium Acetate</td><td>Fisher</td><td>P171-500</td><td>needed for media</td></tr><tr><td>Glycerol</td><td>Fisher</td><td>G33-500</td><td>needed for media</td></tr><tr><td>Black 96 well glass bottom plate</td><td>MatTek</td><td>PBK96G-1.5.5-F</td><td>needed for step 2.4</td></tr></tbody></table>

efficient sporulation of saccharomyces cerevisiae in a 96 multiwell format

Efficient Sporulation of Saccharomyces cerevisiae in a 96 Multiwell Format

During times of nutritional stress, Saccharomyces cerevisiae undergoes gametogenesis, known as sporulation. Diploid yeast cells that are starved for nitrogen and carbon will initiate the sporulation process. The process of sporulation includes meiosis followed by spore formation, where the haploid nuclei are packaged into environmentally resistant spores. We have developed methods for the efficient sporulation of budding yeast in 96 multiwell plates, to increase the throughput of screening yeast cells for sporulation phenotypes. These methods are compatible with screening with yeast containing plasmids requiring nutritional selection, when appropriate minimal media is used, or with screening yeast with genomic alterations, when a rich presporulation regimen is used. We find that for this method, aeration during sporulation is critical for spore formation, and have devised techniques to ensure sufficient aeration that are compatible with the 96 multiwell plate format. Although these methods do not achieve the typical ~80% level of sporulation that can be achieved in large-volume flask based experiments, these methods will reliably achieve about 50-60% level of sporulation in small-volume multiwell plates.

To assess this protocol, sporulation efficiencies obtained from sporulating cells in multiwell plates (as described above) were compared to cells sporulated using larger volumes in flasks (Table 2). The use of multiwell plates did not achieve the high efficiency seen when sporulating in flasks, where ~80% efficiency can be routinely seen. Sporulating in multiwell plates with proper aeration (provided by glass beads or stir bars) can achieve sufficient sporulation efficien...

Here, sporulation of Saccharomyces cerevisiae is carried out in a 96 multiwell format.

During times of nutritional stress, Saccharomyces cerevisiae undergoes gametogenesis, known as sporulation. Diploid yeast cells that are starved for ...

The overall goal of this protocol is to sporulate budding yeast efficiently in a 96-well format. Although many large-scale screens have been carried out on the budding yeast, high-throughput studies looking at meiosis and sporulation have been limited. The technique described in this video has the advantage of sporulating yeast efficiently in a cost-effective manner in a 96-well format compatible with high-throughput screening.I first got the idea for this method because I wanted to use a tiled two micron plasmid library in order to screen for high copy suppressors of a mutant that could not form refractile spores. Initially, my sporulation efficiencies were poor in the 96-well format. I found this was due to inadequate aeration.Begin this procedure by thawing the SK1 yeast strain onto a yeast extract peptone glycerol or YPG plate. Use a sterile stick to scrape a small amount of cells out of the freezer vial containing the glycerol stock and spread it onto a YPG plate. Grow the yeast for 12 to 16 hours at 30 degrees Celsius.Next, streak the yeast from the YPG plate onto a yeast extract peptone dextrose, or YPD, plate for single colones. Grow the yeast on the YPD plate for 24 to 48 hours at 30 degrees Celsius. After 24 to 48 hours of growth on YPD solid media, start a 25 milliliter YPD culture using a single colony from the YPD plate.Grow this culture overnight in a 30 degree Celsius shaking incubator at 220 RPM until the cells reach an OD600 of 4.0 to 7.0. On the following day, use an appropriate amount of cells from the YPD culture to start a 125 milliliter culture in yeast extract peptone acetate, or YPA, with an OD600 of 0.1. Grow the culture in a 30 degree Celsius shaking incubator at 220 RPM until the OD600 is between 1.3 and 1.5.Transfer the culture to centrifuge tubes and spin at 1800X G in a tabletop centrifuge for five minutes to pellet the cells. Wash the cells once with a 0.5 volume of sterile autoclaved deionized water. Spin again and discard the water.Resuspend the cells in a 1X volume of sporulation media. To prepare cells of different genotypes, cells from thawed frozen stocks in a 96 multiwell plate are first transferred onto YPG solid media. Flame a 96 prong frogger and then cool it momentarily on a plate of solid media before touching it to the yeast colonies.Grow the yeast overnight at 30 degrees Celsius. On the following day, transfer the cells from YPG solid media onto the YPD or selective solid media, depending on the genotype of the strain. YPD is used in this demonstration.Grow the yeast at 30 degrees Celsius until colonies are formed for each strain. Aliquot 1.2 milliliters of YPD liquid media into each well of a 96 deep well plate. Transfer the cells from the solid media into liquid media.Cover the plate with a plastic lid from a rectangular petri plate and hold the lid in place using a piece of tape to minimally restrict air circulation. Grow the cells overnight in a 30 degree Celsius shaker at 220 RPM. On the following day, centrifuge at 1800X G for five minutes.Pour off the media and add 500 microliters of YPA to each well. And resuspend the pelleted cells. Cover the plate with a plastic lid held in place by tape.Grow the cells for 15 hours in a 30 degree Celsius shaking incubator at 220 RPM. To provide proper aeration for efficient sporulation, add into each well of a 96-well plate either one three millimeter sterile solid glass bead or a sterile five millimeter by two millimeter magnetic stir bar. If all cells are of the same genotype, aliquat 500 microliters of cells plus media into each well of the 96-multiwell plate.Cover the plate with a plastic lid held in place by tape. If cells are of different genotypes, spin the cells that are in YPA at 1800X G for five minutes and pour off the media. Add 500 microliters of sporulation media to each well.And resuspend the pelleted cells in the sporulation media. Cover the plate with a plastic lid held in place by tape. If using glass beads, place the samples in a shaking incubator at 30 degrees Celsius and shake at 220 RPM for sporulation.If using magnetic stir bars, place the samples on a stir plate inside of a 30 degrees Celsius incubator for sporulation. The exact stir speed for the magnetic bars is not very important, as long as all of the bars are moving energetically and the culture is aerated. 36 hours later, retrieve the samples to monitor progression through sporulation.Withdraw six microliters of cells from each sporulating culture and add to 24 microliters of sporulation media in a 96-well coverslip plate. Leave the cells to settle for five minutes before examining them using an inverted microscope. A representative sporulation of two different strains is shown in these images of cells visualized using a 63X objective on an inverted microscope.Refractile tetrads, indicated by the arrowheads, can be seen in the wild-type culture. But not in the culture containing the sporulation-deficient smk1 delete cells. Comparisons were made between sporulation efficiencies from cells sporulated in multi-well plates and cells sporulated using larger volumes in flasks.The use of multi-well plates did not achieve the high efficiency routinely seen when using the more typical protocol of sporulating in flasks. Sporulating in multi-well plates with proper aeration can achieve sufficient sporulation efficiencies greater than 50%with the best results obtained using a five millimeter stir bar. However, given the high cost of the small stir bars, the efficiencies obtained using glass beads are comparable.Although both five millimeter and seven millimeter stir bars fit within the well of a 96-multiwell plate, using a seven millimeter stir bar resulted in poor sporulation efficiency. The seven millimeter stir bar in a well tends to interact with a stir bar in an adjacent well. Preventing the bars from stirring properly and providing adequate aeration to the culture.After watching this video, you should have a good understanding of how to efficiently sporulate yeast cells in liquid culture in the 96-well format. Once mastered, this process can be completed in six days, if done properly. This procedure can be used for screening different mutant strains, plasmids, or small molecule inhibitors for their effect on meiosis and sporulation.After it's development, this technique was used to study the regulation of meiotic cell cycle and how cytokinesis and meiosis are coupled in sporulation in Saccharomyces cerevisiae.

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Research

JoVE Journal

Biology

Micromanipulation of yeast cells is needed for meiotic genetic analysis or to select diploid zygotes. These micromanipulations are carried out using the microneedle of a dissection microscope. The microneedle is used to relocate cells and is controlled by a micromanipulator which are available with various degrees of automation.

Dissection of Saccharomyces Cerevisiae Asci

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.

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

In this protocol, gene expression in yeast (Saccharomyces cerevisiae) is changed after exposure to oxidative stress induced by the addition of hydrogen peroxide (H2O2), an oxidizing agent.

Microarray Analysis for Saccharomyces cerevisiae

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High-throughput Yeast Plasmid Overexpression Screen

We have developed comprehensive, unbiased genome-wide screens to understand gene-drug and gene-environment interactions. Methods for screening these mutant collections are presented.

Competitive Genomic Screens of Barcoded Yeast Libraries

The Green Monster method enables the rapid assembly of multiple deletions marked with a reporter gene encoding green fluorescent protein. This method is based on driving yeast strains through repeated cycles of sexual assortment of deletions and fluorescence-based enrichment of cells carrying more deletions.

The Green Monster Process for the Generation of Yeast Strains Carrying Multiple Gene Deletions

We present a detailed protocol to construct and screen mutant libraries for directed evolution campaigns in Saccharomyces cerevisiae.

Directed Evolution Method in Saccharomyces cerevisiae: Mutant Library Creation and Screening

Here we present a protocol to estimate the respiratory and fermentative metabolism by fitting the exponential growth of Saccharomyces cerevisiae to the exponential growth equation. Calculation of the kinetic parameters allows for the screening of influences of substances/compounds on fermentation or mitochondrial respiration.

Saccharomyces cerevisiae Exponential Growth Kinetics in Batch Culture to Analyze Respiratory and Fermentative Metabolism

Here, we present live-cell imaging which is a non-toxic microscopy method that allows researchers to study protein behavior and nuclear dynamics in living fission yeast cells during mitosis and meiosis.

Examination of Mitotic and Meiotic Fission Yeast Nuclear Dynamics by Fluorescence Live-cell Microscopy

We present a protocol for lamella preparation of plunge frozen biological specimens by cryo-focused ion beam micromachining for high-resolution structural studies of macromolecules in situ with cryo-electron tomography. The presented protocol provides guidelines for the preparation of high-quality lamellae with high reproducibility for structural characterization of macromolecules inside the Saccharomyces cerevisiae.

Preparation and Cryo-FIB micromachining of Saccharomyces cerevisiae for Cryo-Electron Tomography

The ACT1-CUP1 assay, a copper growth assay, provides a quick readout of precursor messenger RNA (pre-mRNA) splicing and the impact mutant splicing factors have on spliceosomal function. This study provides a protocol and highlights the customization possible to address the splicing question of interest.

ACT1-CUP1 Assays Determine the Substrate-Specific Sensitivities of Spliceosomal Mutants in Budding Yeast

Learn efficient sporulation of Saccharomyces cerevisiae in a 96-well format for high-throughput genetic screening. This optimized aeration method enables cost-effective yeast mutant analysis and plasmid library studies.

Efficient Sporulation of Saccharomyces cerevisiae in a 96 Multiwell Format

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