Differentiation in Yeast: Mechanisms of Mating and Meiosis

酵母的分化：交配和减数分裂的机制

• 批准号: 10458640
• 负责人: Mark David Rose
• 金额: $ 39.86万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10458640
• 关键词: Address; Adenine; Aneuploidy; Animal Model; Animals; Biological; Cell Wall; Cell fusion; Cell membrane; Cell physiology; Cells; Cellular biology; Complex; Defect; Degradation Pathway; Development; Diploidy; Disease; Disseminated Malignant Neoplasm; Eukaryotic Cell; Extracellular Matrix; Fertilization; Genes; Genetic Screening; Genetic Transcription; Germ Cells; Giant Cells; Goals; Haploidy; Health; Homologous Gene; Human; Lead; Mediating; Meiosis; Membrane; Membrane Fusion; Messenger RNA; Methylation; Methyltransferase; Mitosis; Modification; Molecular; Mus; Myoblasts; Nuclear Envelope; Nuclear Fusion; Organism; Partner in relationship; Pathologic; Pathway interactions; Plants; Process; Proteins; Regulation; Research; Role; Saccharomyces cerevisiae; Saccharomycetales; Sexual Reproduction; Signal Transduction; Somatic Cell; Sterility; Testing; Tissues; Transcriptional Regulation; Translational Regulation; Viral; Yeasts; fungus; muscle form; novel; protein degradation; zygote

Eukaryotic cells fuse during fertilization to produce diploid zygotes that go on to differentiate into specialized cells during development. Somatic cell fusion also occurs during development to produce multinucleate tissues, such as myoblast fusion to form muscle. Diploid organisms may then undergo meiosis to produce haploid gametes for subsequent fertilization, completing the cycle of sexual reproduction. Cell fusion and meiosis must be tightly regulated. Inappropriate cell fusion, as occurs in some virally-infected cells and metastatic cancers, results in pathological syncytia. Despite advances in elucidating the process of cell fusion, much remains unknown. Meiotic defects may cause aneuploidy, or even sterility. Recent research revealed that meiotic regulation is surprisingly complex. Overlaid on waves of transcriptional regulation are complex layers of mRNA modification and translational regulation which are thought to provide exquisite temporal control. However, much remains to be learned about how meiosis is regulated. The long-term goals of the research in my lab are to understand the fundamental, conserved molecular mechanisms of cell fusion, nuclear fusion, and meiotic regulation using one of the most powerful model organisms, the budding yeast Saccharomyces cerevisiae. During yeast mating and somatic cell fusion, cells must signal that they are in contact and competent to fuse, remove the extracellular matrix separating them, and fuse the plasma membranes. Each step is only poorly understood. We have shown that in yeast, as in mouse myoblasts, Cdc42p is a key regulator of cell fusion. We will address how cell contact regulates Cdc42p and how Cdc42p in turn mediates cell fusion, focusing on membrane curvature and the cell wall integrity pathway. Using a novel genetic screen, we will pursue identification of the yeast membrane fusogen. After mating and cell fusion, many induced proteins may be hazardous and must be rapidly degraded. We discovered that Srl4p stabilizes mating-induced proteins by inhibiting a branch of the proteasomal degradation pathway. We will examine how Srl4p differentially regulates the turnover of proteins in mating and mitosis. After fertilization in many organisms, the pronuclei fuse. Nuclear fusion is a challenging biological problem – how do the two membranes fuse sequentially and in register? We identified Kar5p, a protein conserved in plants, animals, and fungi, as mediating nuclear envelope fusion; however, its precise role is unknown. We will test our hypothesis that Kar5p acts as a novel inner nuclear envelope fusogen. In meiosis, mRNA N6-adenine methylation has been revealed to be a critical regulator, although its functions are not yet understood. Kar4p is the yeast homologue of human METTL14, a core component of the methyl-transferase. Surprisingly, we found that Kar4p regulates both meiotic transcription and meiotic protein levels. We will examine how Kar4p regulates meiosis at multiple levels, testing potential roles in transcription, translational regulation, and mRNA modification. Our studies will aid the understanding of basic conserved mechanisms of cell fusion, nuclear membrane fusion, and meiosis.

真核细胞在受精过程中融合以产生二倍体Zygotes，这些合子继续分为专业 开发过程中的细胞。在发育过程中也会发生体细胞融合以产生多核 组织，例如成肌细胞融合以形成肌肉。二倍体生物可能会发生减数分裂以产生 单倍性游戏用于随后的受精，完成了有性繁殖的循环。细胞融合和 减数分裂必须受到严格的调节。不适当的细胞融合，如某些几乎感染的细胞中发生的那样 转移性癌症，导致病理性的晕厥。尽管在阐明细胞融合过程方面取得了进步，但 仍然有很多未知的地方。减数分裂缺陷可能会导致非整倍性甚至不育。最近的研究表明 减数分裂的调节非常复杂。在转录调节波上覆盖很复杂 mRNA修改和翻译调节层，被认为提供独家临时性 控制。但是，关于如何调节减数分裂还有很多待了解。长期目标 我实验室的研究是了解细胞融合的基本，配置的分子机制 使用最强大的模型生物之一的融合和减数分裂调节，即萌芽的酵母 酿酒酵母。在酵母交配和体细胞融合期间，细胞必须发出信号表明它们在 接触并有能力融合，去除分离它们的细胞外基质，然后融合等离子体 膜。每个步骤只能理解。我们已经表明，在酵母中，就像在鼠标成肌细胞中一样 CDC42P是细胞融合的关键调节剂。我们将解决细胞触点如何调节CDC42P以及CDC42P如何在 转弯介导细胞融合，重点放在膜曲率和细胞壁完整性途径上。使用小说 遗传筛选，我们将追求酵母膜融合原的鉴定。交配和细胞融合后， 许多诱导的蛋白质可能是危险的，必须迅速降解。我们发现SRL4P稳定 通过抑制蛋白酶体降解途径的分支来诱导的蛋白质。我们将研究如何 SRL4P对交配和有丝分裂中蛋白质的周转不同。受精后 有机体，原核保险丝。核融合是一个挑战生物学问题 - 两个膜如何 顺序融合并在登记处？我们确定了Kar5p，一种构成在植物，动物和真菌中的蛋白质，是 介导核包络融合；但是，其精确作用尚不清楚。我们将测试KAR5P的假设 充当一种新型的内部核包络富蛋白。在减数分裂中，mRNA N6-腺嘌呤甲基化已显示 成为关键的调节剂，尽管尚未理解其功能。 KAR4P是人类的酵母同源物 mettl14，甲基转移酶的核心成分。令人惊讶的是，我们发现Kar4p调节了这两个 减数分裂转录和减数分裂蛋白水平。我们将研究KAR4P如何调节多个的减数分裂 水平，测试在转录，翻译调节和mRNA修饰中的潜在作用。我们的研究将 有助于理解细胞融合，核膜融合和减数分裂的基本组成机制。