A MAP Kinase that controls the post-meiotic phase of the yeast life cycle.

项目摘要/摘要：减数分裂是产生单倍体配子的细胞分裂的特殊形式 来自二倍体前体。它对几乎所有真核生物的生命周期都是必不可少的。理解 减数分裂调控机制与人类健康有关，因为减数分裂缺陷会导致不孕、癌症、 和先天缺陷。面包酵母是研究减数分裂发育的优秀模式系统。作为对.的回应 饥饿时，二倍体细胞进入减数分裂，并在母细胞内产生四个单倍体细胞。早些时候 事件包括减数分裂DNA复制、同源配对和基因重组。在完成后 基因重组，细胞经历两轮染色体分离，没有介入的S期。 在第二次减数分裂后，单倍体产物被包裹在孢子壁中，以保护 来自环境侮辱的单倍体。尽管酵母菌已经教会了我们很多关于减数分裂的知识--S期、前期和 除了减数分裂外，人们对减数分裂发生后发生的过程知之甚少。一 我们对这个程序的减数分裂后阶段知之甚少的原因是孢子壁是实验性的 不可穿透的；在自然条件下提取大分子或使用 直到最近，免疫荧光方法几乎是不可能的。赞助商之前的工作 实验室已经确定了一种名为Smk1的减数分裂特异性MAPK，它控制着孢子的减数分裂后程序 队形。这导致了发现Smk1激活了晚期减数分裂特异基因的表达，这 是在孢子壁组装后独特表达的。这项提议利用了工程化的 酵母菌产生可渗透的孢子壁，从而使细胞内和细胞核内发生的事件 可以研究减数分裂发育的后期阶段。该提案还利用了工程化的 对可用于打开Smk1的细胞通透性嘌呤类似物(Smk1-AS)敏感的Smk1的形式 然后关机。穿透孢子壁的突变与smk1-as结合在一个遗传背景中 以高度同步的方式进行减数分裂，这将被用来定义完整的晚 由Smk1调控的减数分裂特异基因(目标1)。我们还将测试Smk1是 被招募到减数分裂后期特异转录启动子(目标2)。初步数据显示，Smk1 我们还将检验这一假设，以及是否 这些修饰发生在减数分裂后期的特定基因转录过程中(目标3)。的研究 酵母中减数分裂事件是如何调节的，这可能为人类配子发生提供洞察，这具有临床意义 对解决不孕不育、流产和发育障碍的影响。首席调查员(朱莉娅 Lee-Soty)打算在她休假期间在爱德华·温特博士的实验室 费城的托马斯·杰斐逊大学。在项目期之后，PI计划继续采取后续行动 在她的母校(圣约瑟夫大学)与本科生一起学习。

Project Summary/Abstract: Meiosis is the specialized form of cell division that generates haploid gametes from diploid precursors. It is essential for the life-cycles of almost all eukaryotic organisms. Understanding meiotic regulatory mechanisms is relevant to human health since defects in meiosis cause infertility, cancer, and birth defects. Baker's yeast is an outstanding model system to study meiotic development. In response to starvation, diploid cells enter meiotic development and generate four haploid cells within the mother cell. Early events include meiotic DNA replication, homolog pairing, and genetic recombination. After the completion of genetic recombination, cells undergo 2 rounds of chromosome segregation without an intervening S-phase. After the second meiotic division (MII), the haploid products are encased in spore walls that protect the haploids from environmental insults. Although yeast has taught us much about meiotic S-phase, prophase, and the meiotic divisions, much less is known about the processes that occur after MII has taken place. One reason we know so little about the post-meiotic phase of this program is that the spore walls are experimentally impenetrable; extracting macromolecules under native conditions or monitoring molecules using immunofluorescence methods has until recently been nearly impossible. Previous work in the sponsor's laboratory has identified a meiosis-specific MAPK named Smk1 that controls the post-meiotic program of spore formation. This led to the discovery that Smk1 activates the expression of late meiosis-specific genes, which are uniquely expressed after the spore wall has assembled. This proposal takes advantage of engineered yeast strains that produce permeable spore walls so that the intracellular and nuclear events that occur during the late stages of meiotic development can be studied. The proposal also takes advantage of engineered forms of Smk1 that are sensitive to cell-permeable purine analogs (smk1-as) that can be used to turn Smk1 on and off. Mutations that permeabilize the spore wall with smk1-as are combined in a genetic background that undergoes meiosis in a highly synchronous manner, and this will be used to define the complete set of late meiosis-specific genes that are regulated by Smk1 (aim 1). We will also test the hypothesis that Smk1 is recruited to late meiosis-specific transcriptional promoters (aim 2). Preliminary data suggests that Smk1 phosphorylates the C terminal domain of RNA polymerase, and we will also test this hypothesis and whether these modifications take place at late meiosis specific genes as they are being transcribed (aim 3). Studies of how meiotic events are regulated in yeast may provide insights into human gametogenesis, which have clinical implications in solving infertility, miscarriages, and developmental disorders. The principal investigator (Julia Lee-Soety) intends to conduct this work during her sabbatical leave in Dr. Edward Winter's laboratory at the Thomas Jefferson University in Philadelphia. Beyond the project period, the PI plans to continue follow-up studies with undergraduate research students at her home institution (Saint Joseph's University).