In response to nutrient starvation the budding yeast Saccharomyces cerevisiae abandons mitotic proliferation and embarks on a differentiation process leading through meiosis to the formation of haploid spores. This process is driven by cascading waves of meiosis-specific gene expression. The early meiosis-specific genes are repressed during mitotic proliferation by DNA-binding protein Ume6 in combination with repressors Rpd3 and Sin3. The expression of meiosis-specific transcription factor Ime1 leads to activation of the early meiosis-specific genes. We investigated the stability and promoter occupancy of Ume6 in sporulating cells and determined that it remains bound to early meiosis-specific gene promoters when those genes are activated. Further we find that repressor Rpd3 remains associated with Ume6 after the transactivator Ime1 has joined the complex and that Gcn5 and Tra1 components of the SAGA complex bind to the promoter of IME2 in an Ime1 dependent fashion to induce transcription of the early meiosis-specific genes. Our investigation supports a model whereby Ume6 provides a platform allowing recruitment of both activating and repressing factors to coordinate expression of the early meiosis-specific genes in Saccharomyces cerevisiae

响应营养不足，发芽酵母酿酒酵母放弃有丝分裂增殖，并开始通过减数分裂导致单倍体孢子形成的分化过程。此过程是由减数分裂特异性基因表达的级联波驱动的。DNA结合蛋白Ume6与阻遏物Rpd3和Sin3结合，可在有丝分裂增殖过程中抑制早期减数分裂特异的基因。减数分裂特异性转录因子Ime1的表达导致早期减数分裂特异性基因的激活。我们调查了Ume6在孢子形成细胞中的稳定性和启动子占有率，并确定当这些基因被激活时，它仍与早期减数分裂特异的基因启动子结合。IME2以Ime1依赖的方式诱导早期减数分裂特异基因的转录。我们的研究支持一个模型，其中Ume6提供了一个平台，该平台允许募集激活因子和阻遏因子以协调酿酒酵母中早期减数分裂特异基因的表达。