Cell Cycle Regulation In Oogenesis

卵子发生中的细胞周期调控

• 批准号: 8553886
• 负责人: MARY A LILLY
• 金额: $ 92万
• 依托单位: EUNICE KENNEDY SHRIVER NATIONAL INSTITUTE OF CHILD HEALTH & HUMAN DEVELOPMENT
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8553886
• 关键词: Adopted; Alleles; Animal Model; Autophagocytosis; Biochemical; Biological; Biological Models; Cell Cycle; Cell Cycle Regulation; Cell Nucleus; Cell physiology; Cells; Cellular Stress; Chromosomes; Complex; Congenital Abnormality; Cytoplasm; Defect; Development; Drosophila genus; Drosophila melanogaster; Event; Female; Gametogenesis; Genes; Genetic; Genetic Screening; Germ Cells; Germ Lines; Goals; Growth; Homologous Gene; Hormonal; Human; Laboratories; Lysosomes; Maintenance; Mediating; Meiosis; Metabolism; Modeling; NPR2 gene; Nuclear Pore Complex; Nuclear Pore Complex Proteins; Nurses; Nutrient; Oocytes; Oogenesis; Ovarian Cysts; Pathway interactions; Proteins; Reporting; Reproductive Biology; Reproductive Medicine; Role; Signal Pathway; Spontaneous abortion; Tissues; Tumor Suppressor Genes; Vacuole; Work; Yeasts; egg; macromolecule; member; mutant; novel; nuclear pore complex protein p107; programs; protein complex; residence; Adopted; Alleles; Animal Model; Autophagocytosis; Biochemical; Biological; Biological Models; Cell Cycle; Cell Cycle Regulation; Cell Nucleus; Cell physiology; Cells; Cellular Stress; Chromosomes; Complex; Congenital Abnormality; Cytoplasm; Defect; Development; Drosophila genus; Drosophila melanogaster; Event; Female; Gametogenesis; Genes; Genetic; Genetic Screening; Germ Cells; Germ Lines; Goals; Growth; Homologous Gene; Hormonal; Human; Laboratories; Lysosomes; Maintenance; Mediating; Meiosis; Metabolism; Modeling; NPR2 gene; Nuclear Pore Complex; Nuclear Pore Complex Proteins; Nurses; Nutrient; Oocytes; Oogenesis; Ovarian Cysts; Pathway interactions; Proteins; Reporting; Reproductive Biology; Reproductive Medicine; Role; Signal Pathway; Spontaneous abortion; Tissues; Tumor Suppressor Genes; Vacuole; Work; Yeasts; egg; macromolecule; member; mutant; novel; nuclear pore complex protein p107; programs; protein complex; residence

During the formation of the female gamete the cell cycle events of meiosis must be precisely coordinated with the ongoing differentiation of the oocyte. We use Drosophila melanogaster as a model system to define the pathways that regulate early meiotic progression and oocyte development. To achieve this goal we use forward genetic, biochemical and cell biological approaches. From our studies we have identified several genes, including missing oocyte (mio) and seh1, which define a new pathway that influences both the maintenance of the meiotic cycle and the oocyte fate. The mio gene was identified in a forward genetic screen for mutants effecting cell cycle regulation and oocyte differentiation in early ovarian cysts. In mio mutants, the oocyte enters the meiotic cycle and accumulates oocyte specific markers. Ultimately, however, mio oocytes exit the meiotic cycle and adopt an alternative nurse cell fate. The mio gene encodes a 975 AA protein that is highly conserved from yeast to humans. We have demonstrated that the MIO protein physically associates with the Nucleoporin SEH1. SEH1 is a component of the Nup107-160 complex, the major structural subcomplex of the NPC. The nuclear pore complex (NPC) mediates transport of macromolecules between the nucleus and the cytoplasm. Recent evidence indicates that structural nucleoporins, the building blocks of the NPC, have a variety unanticipated cellular functions. Consistent with these reports we find that the structural nucleoporin SEH1 has an unexpected role during Drosophila oogenesis. As is observed in mio mutants, in seh1 mutants a fraction of oocytes fail to maintain the meiotic cycle and develop as pseudo-nurse cells. Moreover, we find that the stability of the MIO protein is greatly diminished in the seh1 mutant background supporting the model that MIO and SEH1 are present in a multi-protein complex. Surprisingly, our characterization of a seh1 null allele indicates that while required in the female germline, seh1 is dispensable for the development of somatic tissues. Our studies support the model that MIO is a novel interacting partner of the conserved nucleoporin SEH1 and add to the growing body of evidence that structural nucleoporins can have novel functions that are independent of their residence at the NPC. Consistent with MIO and SEH1 functioning outside of the context of the NPC, recent reports indicate that MIO and SEH1 homologs from yeast are components of a multi-protein complex called the Seh1-associated complex (SEA-complex). The SEA-complex associates with the vacuole, the functional equivalent of lysosomes in metazoans. In yeast several components of the SEA-complex influence mTor activity upon nutrient limitation. Intriguingly, in humans at least one member of the SEA-complex, NPR2, functions as a tumor suppressor gene. We have determined that in Drosophila the NPR2 protein associates with both MIO and SEH1. Currently, we are working to define the role of NPR2, MIO, SEH1 and other SEA-complex members, in meiotic progression and growth control. Our recent findings suggest that mio and seh1 regulate catabolic metabolism and autophagy in the female germ line. Further studies of the SEA-complex members will elucidate the relationship between the pathways that regulate cellular stress and meiotic progression in metazoans.

在女配子的形成过程中，减数分裂的细胞周期事件必须与卵母细胞的持续分化相协调。我们使用果蝇黑色素果蛋白酶作为模型系统来定义调节早期减数分裂进程和卵母细胞发育的途径。为了实现这一目标，我们使用远期遗传，生化和细胞生物学方法。从我们的研究中，我们确定了几个基因，包括缺失的卵母细胞（MIO）和SEH1，这些基因定义了一种新的途径，从而影响了减数分裂周期和卵母细胞命运的维持。在卵巢早期囊肿的细胞周期调节和卵母细胞分化的突变体中，在正向遗传筛选中鉴定了MIO基因。在MIO突变体中，卵母细胞进入减数分裂周期并积累卵母细胞特定标记。然而，最终，Mio卵母细胞退出减数分裂周期并采用替代性护士细胞命运。 MIO基因编码从酵母到人高度保守的975 AA蛋白。 我们已经证明了MIO蛋白与核孔蛋白SEH1物理相关。 SEH1是NUP107-160复合物的组成部分，NPC的主要结构子复杂。核孔复合物（NPC）介导细胞核和细胞质之间的大分子的转运。最近的证据表明，结构性核孔（NPC的构建基块）具有多样性的意外细胞功能。与这些报告一致，我们发现结构性核孔蛋白SEH1在果蝇中具有出乎意料的作用。正如在MIO突变体中观察到的那样，在SEH1突变体中，卵母细胞的一部分无法维持减数分裂循环，并以伪核细胞的形式发展。此外，我们发现MIO蛋白的稳定性在SEH1突变体背景中大大降低，该模型支持MIO和SEH1存在于多蛋白质复合物中。令人惊讶的是，我们对SEH1无效等位基因的表征表明，尽管在女性种系中需要SEH1，但对于体细胞组织的发展是可分配的。我们的研究支持了MIO是保守核孔蛋白SEH1的新型相互作用的模型，并增加了越来越多的证据体系，即结构性核孔蛋白可以具有独立于其在NPC的住所的新功能。 与NPC背景之外的MIO和SEH1一致，最近的报道表明，来自酵母的MIO和SEH1同源物是称为SEH1相关复合物（Sea-complex）的多蛋白质复合物的成分。 Sea-Qumplex与液泡相关，是后生动物中溶酶体的功能。在酵母中，Sea-Amplex的几个成分会影响营养限制的MTOR活性。 有趣的是，在人类中，NPR2的至少一个成员充当肿瘤抑制基因。我们已经确定在果蝇中，NPR2蛋白与MIO和SEH1均相关。目前，我们正在努力定义NPR2，MIO，SEH1和其他Sea-Amplex成员在减数分裂进程和生长控制中的作用。 我们最近的发现表明，MIO和SEH1调节雌性生殖系中的分解代谢代谢和自噬。对Sea-Ampemplex成员的进一步研究将阐明调节后生动物细胞应激和减数分裂进程的途径之间的关系。