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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

SUB1 genetic interaction with HOS2.(A) Cell morphology of WT, sub1Δ, hos2Δ and sub1Δ hos2Δ (n) MATa cells photographed after 1 day of growth in liquid YPD medium. sub1Δ hos2Δ (n) double mutant cells show schmoo formation (indicated by arrows). (B) sub1Δ hos2Δ (n) double mutant strain shows agar invasion. WT, sub1Δ, hos2Δ and sub1Δ hos2Δ (n) strains were spotted on YPD medium and after 3 days of growth, plates were photographed, washed and re-photographed. (C) Sporulation was measured after 72 and 90 hours of transfer of cells from presporulation to sporulation medium. At least 600 cells were counted at each time point in two or three independent replicate experiments.
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pone.0132350.g006: SUB1 genetic interaction with HOS2.(A) Cell morphology of WT, sub1Δ, hos2Δ and sub1Δ hos2Δ (n) MATa cells photographed after 1 day of growth in liquid YPD medium. sub1Δ hos2Δ (n) double mutant cells show schmoo formation (indicated by arrows). (B) sub1Δ hos2Δ (n) double mutant strain shows agar invasion. WT, sub1Δ, hos2Δ and sub1Δ hos2Δ (n) strains were spotted on YPD medium and after 3 days of growth, plates were photographed, washed and re-photographed. (C) Sporulation was measured after 72 and 90 hours of transfer of cells from presporulation to sporulation medium. At least 600 cells were counted at each time point in two or three independent replicate experiments.

Mentions: Genome-wide genetic interaction screens with vegetatively growing haploid cells, report Sub1 interactions with members of histone deacetylase complex, Set3C [27–30]. Here, we studied the genetic interaction of SUB1 with HOS2, a subunit of Set3 complex. SUB1 and HOS2 are reported to show negative genetic interaction in haploid cells [27,29,30]. Moreover, HOS2 is previously reported to be required for the response to secretory stress and the cells lacking Hos2 exhibit tunicamycin sensitivity [31]. We confirmed the sensitivity of hos2Δ strain to tunicamycin and further studied its genetic interaction with SUB1 by examining its effects in sub1Δ hos2Δ strain. We observed a partial rescue of tunicamycin sensitivity in haploid sub1Δ hos2Δ cells (S5 Fig). Interestingly, a schmoo phenotype was noted in 28–30% of sub1Δ hos2Δ haploid cells which were grown in YPD medium, a phenotype not seen in either of the single mutants (Fig 6A). In isw2Δ cells, a mutant in a chromatin-remodelling complex subunit, autocrine activation of the pheromone response pathway results in schmoo formation and pheromone-induced agar invasion [32]. Thus, we investigated haploid sub1Δ hos2Δ double mutant for agar invasion and even on YPD medium sub1Δ hos2Δ cells display agar invasion (Fig 6B). Deletion of Hos2 is also reported to increase asci formation [33,34]. Genetic interactions between Sub1 and Hos2 during sporulation are not yet studied. Therefore, we generated homozygous a diploid sub1Δ hos2Δ strain and examined sporulation frequency of the double mutant as compared to the diploid with each of the single mutant loci and to wild-type diploids. hos2Δ diploids showed a marginal increase in sporulation when compared to the wild-type (Fig 6C). Moreover, we observed that sporulation efficiency of sub1Δ hos2Δ diploids was intermediate between those of the either single mutant strains. Taken together, these results suggest that SUB1 and HOS2 genetically interact during sporulation and may not be involved in a linear pathway.


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

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

SUB1 genetic interaction with HOS2.(A) Cell morphology of WT, sub1Δ, hos2Δ and sub1Δ hos2Δ (n) MATa cells photographed after 1 day of growth in liquid YPD medium. sub1Δ hos2Δ (n) double mutant cells show schmoo formation (indicated by arrows). (B) sub1Δ hos2Δ (n) double mutant strain shows agar invasion. WT, sub1Δ, hos2Δ and sub1Δ hos2Δ (n) strains were spotted on YPD medium and after 3 days of growth, plates were photographed, washed and re-photographed. (C) Sporulation was measured after 72 and 90 hours of transfer of cells from presporulation to sporulation medium. At least 600 cells were counted at each time point in two or three independent replicate experiments.
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Related In: Results  -  Collection

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

pone.0132350.g006: SUB1 genetic interaction with HOS2.(A) Cell morphology of WT, sub1Δ, hos2Δ and sub1Δ hos2Δ (n) MATa cells photographed after 1 day of growth in liquid YPD medium. sub1Δ hos2Δ (n) double mutant cells show schmoo formation (indicated by arrows). (B) sub1Δ hos2Δ (n) double mutant strain shows agar invasion. WT, sub1Δ, hos2Δ and sub1Δ hos2Δ (n) strains were spotted on YPD medium and after 3 days of growth, plates were photographed, washed and re-photographed. (C) Sporulation was measured after 72 and 90 hours of transfer of cells from presporulation to sporulation medium. At least 600 cells were counted at each time point in two or three independent replicate experiments.
Mentions: Genome-wide genetic interaction screens with vegetatively growing haploid cells, report Sub1 interactions with members of histone deacetylase complex, Set3C [27–30]. Here, we studied the genetic interaction of SUB1 with HOS2, a subunit of Set3 complex. SUB1 and HOS2 are reported to show negative genetic interaction in haploid cells [27,29,30]. Moreover, HOS2 is previously reported to be required for the response to secretory stress and the cells lacking Hos2 exhibit tunicamycin sensitivity [31]. We confirmed the sensitivity of hos2Δ strain to tunicamycin and further studied its genetic interaction with SUB1 by examining its effects in sub1Δ hos2Δ strain. We observed a partial rescue of tunicamycin sensitivity in haploid sub1Δ hos2Δ cells (S5 Fig). Interestingly, a schmoo phenotype was noted in 28–30% of sub1Δ hos2Δ haploid cells which were grown in YPD medium, a phenotype not seen in either of the single mutants (Fig 6A). In isw2Δ cells, a mutant in a chromatin-remodelling complex subunit, autocrine activation of the pheromone response pathway results in schmoo formation and pheromone-induced agar invasion [32]. Thus, we investigated haploid sub1Δ hos2Δ double mutant for agar invasion and even on YPD medium sub1Δ hos2Δ cells display agar invasion (Fig 6B). Deletion of Hos2 is also reported to increase asci formation [33,34]. Genetic interactions between Sub1 and Hos2 during sporulation are not yet studied. Therefore, we generated homozygous a diploid sub1Δ hos2Δ strain and examined sporulation frequency of the double mutant as compared to the diploid with each of the single mutant loci and to wild-type diploids. hos2Δ diploids showed a marginal increase in sporulation when compared to the wild-type (Fig 6C). Moreover, we observed that sporulation efficiency of sub1Δ hos2Δ diploids was intermediate between those of the either single mutant strains. Taken together, these results suggest that SUB1 and HOS2 genetically interact during sporulation and may not be involved in a linear pathway.

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