Posttranscriptional Regulation of Flocculation in Fission Yeast

絮凝是酵母的一种固有特性，它将单个细胞聚集成称为絮凝体的团块。絮凝表型在酵母工业中非常重要，因为它允许从生物技术产品中高效和经济地去除细胞的方法。与絮凝相关的细胞表面蛋白也参与侵入性生长和生物膜的形成，这有助于致病酵母的毒力和抗真菌抗性。因此，酵母絮凝在这些领域的重大影响突出了充分理解这一过程是如何调节的重要性。******不成比例的努力主要集中在转录（mRNA合成）而不是转录后（mRNA稳定性和翻译）控制酵母絮凝。在任何酵母模型系统中，絮凝在转录后水平上的遗传控制尚不清楚。我们最近在裂糖酵母中发现了一种具有絮凝作用的蛋白。Pumilio （Puf）蛋白家族通过直接与mRNA靶点亚群相互作用，诱导其转换、抑制其翻译并影响细胞定位，从而调控基因的转录后表达。我们的目标是应用遗传学、细胞生物学、生物化学和功能基因组学在裂变酵母模型系统中的强大组合来阐明Pumilio蛋白在絮凝中的功能。本研究计划的具体目的是确定该Pumilio蛋白的mRNA靶点、转录后调控模式和蛋白伴侣。我们还将筛选约3000个缺失突变株的絮凝缺陷，以确定控制这一过程的新基因。我们的观点是，这项研究将导致酵母絮凝过程中基因转录后调控的新机制见解。所产生的知识将对酵母工业有用，并有可能确定致病性酵母的新药物靶点。此外，这项研究也将有可能揭示所有真核生物转录后控制的一般主题或规则。**

Flocculation is an inherent property of yeasts that involves the aggregation of individual cells into clumps called flocs. The flocculent phenotype is very important in the yeast industry as it allows for an efficient and cost-effective method of cell removal from the biotechnological product. Related cell surface proteins to those involved in flocculation are also implicated in invasive growth and biofilm formation which contribute to the virulence and antifungal resistance of pathogenic yeasts. Therefore, the significant impact of yeast flocculation in these areas highlights the importance of fully comprehending how this process is regulated. ******A disproportionate effort has focused mainly on transcriptional (mRNA synthesis) rather than posttranscriptional (mRNA stability and translation) control of yeast flocculation. The genetic control of flocculation in any yeast model system at the posttranscriptional level is not well understood. We have recently discovered a Pumilio protein with a flocculation role in the fission yeast Schizosaccharomces pombe. The Pumilio (Puf) protein family posttranscriptionally regulate gene expression by interacting directly with a subset of mRNA targets to induce their turnover, repress their translation and affect cellular localization. Our goal is to apply a powerful combination of genetics, cell biology, biochemistry and functional genomics in the fission yeast model system to elucidate Pumilio protein function in flocculation. The specific objectives of this research proposal are to determine the mRNA targets, mode of posttranscriptional control and protein partners of this Pumilio protein. We will also screen a collection of approximately 3000 deletion mutant strains for defects in flocculation to identify novel genes that control this process. Our view is that this research will lead to novel mechanistic insights in the posttranscriptional regulation of genes in yeast flocculation. The knowledge generated would be useful to the yeast industry and potentially identify new drug targets for pathogenic yeasts. Furthermore, this research will also have the potential to reveal general themes or rules of posttranscriptional control across all eukaryotes. **