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SUB1 Plays a Negative Role during Starvation Induced Sporulation Program in Saccharomyces cerevisiae.

Gupta R, Sadhale PP, Vijayraghavan U - PLoS ONE (2015)

Bottom Line: Deletion of SUB1 gene significantly increased sporulation efficiency as compared to the wild-type cells in S288c genetic background.Deletion of SUB1 increased middle sporulation gene transcript levels with no effect on their induction kinetics.Taken together, our results suggest that SUB1 acts as a negative regulator of sporulation.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India.

ABSTRACT
Saccharomyces cerevisiae Sub1 is involved in several cellular processes such as, transcription initiation, elongation, mRNA processing and DNA repair. It has also been reported to provide cellular resistance during conditions of oxidative DNA damage and osmotic stress. Here, we report a novel role of SUB1 during starvation stress-induced sporulation, which leads to meiosis and spore formation in diploid yeast cells. Deletion of SUB1 gene significantly increased sporulation efficiency as compared to the wild-type cells in S288c genetic background. Whereas, the sporulation functions of the sub1(Y66A) missense mutant were similar to Sub1. SUB1 transcript and protein levels are downregulated during sporulation, in highly synchronized and sporulation proficient wild-type SK1 cells. The changes in Sub1 levels during sporulation cascade correlate with the induction of middle sporulation gene expression. Deletion of SUB1 increased middle sporulation gene transcript levels with no effect on their induction kinetics. In wild-type cells, Sub1 associates with chromatin at these loci in a temporal pattern that correlates with their enhanced gene expression seen in sub1Δ cells. We show that SUB1 genetically interacts with HOS2, which led us to speculate that Sub1 might function with Set3 repressor complex during sporulation. Positive Cofactor 4, human homolog of Sub1, complemented the sub1Δ sporulation phenotype, suggesting conservation of function. Taken together, our results suggest that SUB1 acts as a negative regulator of sporulation.

No MeSH data available.


Related in: MedlinePlus

Deletion of SUB1 shows an increase in sporulation efficiency compared to wild type cells.Sporulation was measured at different time points as indicated after transfer of cells from presporulation to sporulation medium. At least 1000 cells were counted at each time point in two independent replicate experiments. Double asterisk indicates P value of < 0.01.
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pone.0132350.g001: Deletion of SUB1 shows an increase in sporulation efficiency compared to wild type cells.Sporulation was measured at different time points as indicated after transfer of cells from presporulation to sporulation medium. At least 1000 cells were counted at each time point in two independent replicate experiments. Double asterisk indicates P value of < 0.01.

Mentions: In a previous whole-genome screen for mutants with altered sporulation efficiency in the Saccharomyces cerevisiae S288c strain, SUB1 locus was identified as a negative regulator of sporulation [17]. Moreover, genome-wide gene expression analysis in the SK1 strain, with synchronized and highly efficient induction of sporulation, showed that SUB1 transcript levels are reduced during sporulation [15,24]. Here, we analyzed the kinetics of asci formation in a diploid strain deleted for both the alleles of SUB1 and compared to the isogenic wild-type strain. In the S288c genetic background, we generated homozygous diploid sub1Δ alleles by crossing haploid deletion strains obtained from Euroscarf. Sporulation of WT and sub1Δ/sub1Δ cells was induced by nitrogen starvation and use of non-fermentable sugar as the sole carbon source. Analysis of sporulation kinetics showed that deletion of SUB1 resulted in an overall increase in sporulation efficiency, with nearly 5-fold increase in sporulation efficiency observed after 72 hours of transfer of sub1Δ/sub1Δ cells to sporulation medium as compared to that of the isogenic wild type diploid strain (Fig 1). Therefore, in agreement with the earlier genome-wide studies, we find that Sub1 plays a negative role in kinetics of sporulation in S288c strain background. We also examined the germination efficiency of haploid spores by dissecting 25 tetrads of sub1Δ/sub1Δ diploid cells (S1 Fig). Out of 100 spores dissected, 97 germinated on rich YPD medium. Therefore we conclude the viabilty of the haploid spores from sub1Δ/sub1Δ diploids is comparable to that from wild-type diploids.


SUB1 Plays a Negative Role during Starvation Induced Sporulation Program in Saccharomyces cerevisiae.

Gupta R, Sadhale PP, Vijayraghavan U - PLoS ONE (2015)

Deletion of SUB1 shows an increase in sporulation efficiency compared to wild type cells.Sporulation was measured at different time points as indicated after transfer of cells from presporulation to sporulation medium. At least 1000 cells were counted at each time point in two independent replicate experiments. Double asterisk indicates P value of < 0.01.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492983&req=5

pone.0132350.g001: Deletion of SUB1 shows an increase in sporulation efficiency compared to wild type cells.Sporulation was measured at different time points as indicated after transfer of cells from presporulation to sporulation medium. At least 1000 cells were counted at each time point in two independent replicate experiments. Double asterisk indicates P value of < 0.01.
Mentions: In a previous whole-genome screen for mutants with altered sporulation efficiency in the Saccharomyces cerevisiae S288c strain, SUB1 locus was identified as a negative regulator of sporulation [17]. Moreover, genome-wide gene expression analysis in the SK1 strain, with synchronized and highly efficient induction of sporulation, showed that SUB1 transcript levels are reduced during sporulation [15,24]. Here, we analyzed the kinetics of asci formation in a diploid strain deleted for both the alleles of SUB1 and compared to the isogenic wild-type strain. In the S288c genetic background, we generated homozygous diploid sub1Δ alleles by crossing haploid deletion strains obtained from Euroscarf. Sporulation of WT and sub1Δ/sub1Δ cells was induced by nitrogen starvation and use of non-fermentable sugar as the sole carbon source. Analysis of sporulation kinetics showed that deletion of SUB1 resulted in an overall increase in sporulation efficiency, with nearly 5-fold increase in sporulation efficiency observed after 72 hours of transfer of sub1Δ/sub1Δ cells to sporulation medium as compared to that of the isogenic wild type diploid strain (Fig 1). Therefore, in agreement with the earlier genome-wide studies, we find that Sub1 plays a negative role in kinetics of sporulation in S288c strain background. We also examined the germination efficiency of haploid spores by dissecting 25 tetrads of sub1Δ/sub1Δ diploid cells (S1 Fig). Out of 100 spores dissected, 97 germinated on rich YPD medium. Therefore we conclude the viabilty of the haploid spores from sub1Δ/sub1Δ diploids is comparable to that from wild-type diploids.

Bottom Line: Deletion of SUB1 gene significantly increased sporulation efficiency as compared to the wild-type cells in S288c genetic background.Deletion of SUB1 increased middle sporulation gene transcript levels with no effect on their induction kinetics.Taken together, our results suggest that SUB1 acts as a negative regulator of sporulation.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India.

ABSTRACT
Saccharomyces cerevisiae Sub1 is involved in several cellular processes such as, transcription initiation, elongation, mRNA processing and DNA repair. It has also been reported to provide cellular resistance during conditions of oxidative DNA damage and osmotic stress. Here, we report a novel role of SUB1 during starvation stress-induced sporulation, which leads to meiosis and spore formation in diploid yeast cells. Deletion of SUB1 gene significantly increased sporulation efficiency as compared to the wild-type cells in S288c genetic background. Whereas, the sporulation functions of the sub1(Y66A) missense mutant were similar to Sub1. SUB1 transcript and protein levels are downregulated during sporulation, in highly synchronized and sporulation proficient wild-type SK1 cells. The changes in Sub1 levels during sporulation cascade correlate with the induction of middle sporulation gene expression. Deletion of SUB1 increased middle sporulation gene transcript levels with no effect on their induction kinetics. In wild-type cells, Sub1 associates with chromatin at these loci in a temporal pattern that correlates with their enhanced gene expression seen in sub1Δ cells. We show that SUB1 genetically interacts with HOS2, which led us to speculate that Sub1 might function with Set3 repressor complex during sporulation. Positive Cofactor 4, human homolog of Sub1, complemented the sub1Δ sporulation phenotype, suggesting conservation of function. Taken together, our results suggest that SUB1 acts as a negative regulator of sporulation.

No MeSH data available.


Related in: MedlinePlus