Cohesin Plays a Dual Role in Gene Regulation and Sister-Chromatid Cohesion During Meiosis in Saccharomyces cerevisiae

Abstract

Sister-chromatid cohesion mediated by cohesin ensures proper chromosome segregation during cell division. Cohesin is also required for postreplicative DNA double-strand break repair and gene expression. The molecular mechanisms of these diverse cohesin functions remain to be elucidated. Here we report that the cohesin subunits Scc3 and Smc1 are both required for the production of the meiosisspecific subunit Rec8 in the budding yeast Saccharomyces cerevisiae. Using a genetic approach, we depleted Scc3 and Smc1 independently in cells that were undergoing meiosis. Both Scc3-and Smc1-depleted cells were inducible for meiosis, but the REC8 promoter was only marginally activated, leading to reduced levels of REC8 transcription and protein production. In contrast, the expression of MCD1, the mitotic counterpart of REC8, was not subject to Scc3 regulation in vegetative cells. We provide genetic evidence to show that sister-chromatid cohesion is not necessary for activation of REC8 gene expression. Cohesin appears to positively regulate the expression of a variety of genes during yeast meiosis. Our results suggest that the cohesin complex plays a dual role in gene regulation and sister-chromatid cohesion during meiotic differentiation in yeast.

A Dual-Color Reporter Assay of Cohesin-Mediated Gene Regulation in Budding Yeast Meiosis

“…On the basis of Western blot results, we have confirmed the efficiency of these conditional alleles (5, 15). …”

Separation of DNA Replication from the Assembly of Break-Competent Meiotic Chromosomes

“…We noted that the chromosomes failed to condense and individualize in the clb5Δ clb6Δ nuclei, indicating that CDK activity and/or DNA replication are likely important for the full assembly of normal meiotic chromosome structures. However, previous analysis of Rec8 staining in cdc6-mn cells indicated that full DNA replication is not required to form full axes [38], [39]. To confirm that axis formation occurs on the same sites in the presence and absence of DNA replication, we localized Rec8, Hop1 and Red1 by whole-genome location analysis.…”

Cohesin: Functions beyond sister chromatid cohesion

“…Rec8‐cohesin further activates the promoter of REC8 to the full extent, and thus meiotic cohesin exhibits a positive feedback on its own transcription [25]. Additionally, mere binding of other cohesin subunits Smc1 and Scc3 on the chromosome were found to be also essential for the expression of REC8 in budding yeast [34].…”