Defining PP1 phosphatase function in paternal meiotic chromosome segregation

描述（由申请人提供）：人类流产和智力低下的主要原因是染色体异常，这可能是由于卵母细胞或精子减数分裂时染色体分离错误造成的。绝大多数新生染色体结构异常是父系起源；因此，了解父系染色体分离机制对于防止自然和辅助生殖失败以及遗传疾病传给后代的潜在可能性至关重要。我们已经确定了雄性特异性PP1磷酸酶的同源物，GSP-3和GSP-4，作为唯一已知的在从蠕虫到人类的精子形成中具有进化保守功能的蛋白质。我们的初步研究表明，在从减数分裂I到减数分裂II的过渡过程中，这些磷酸酶提供了染色体取向动力学的性别特异性调节。GSP-3/4定位于精子减数分裂染色体周围，其模式与着丝点蛋白（染色体和微管的关键连接物）相似。我们还发现GSP-3/4调节特定着丝点组分的性别特异性动态定位。因此，我们的假设是这些PP1磷酸酶是纺锤体微管附着于染色质的关键调节剂，因此在精子减数分裂过程中需要适当的染色体分配。我们将在三个主要领域验证我们的假设：1)染色体定向和微管动力学在MI到MII过渡期间，2)着丝点成分的组成和动态定位，以及3)调节染色质-微管相互作用以使染色体在减数分裂纺锤体上定向的因素的定位。本研究将确定精子减数分裂过程和父本染色质质量和含量的分子标记，这将进一步推动生殖和发育生物学领域的研究。我们的团队还将明确GSP-3/4和减数分裂关键调控因子在父本染色体分离特定阶段的作用，为染色体生物学领域做出重大贡献。这项研究将为临床诊断和治疗的未来发展奠定基础，以识别或预防父亲衍生的染色体异常，这是确保生殖成功和未来后代健康的重要一步。这些研究将包括旧金山州立大学的本科生和硕士生，这是一所历史上为少数民族服务的大学。我们预计在三年的奖励期内，每年将有2-3名学生使用新获得的尖端设备进行具有良好特征的试剂和分析的个人研究项目。因此，他们将获得动手，相关的研究经验和批判性思维技能，以进一步他们在生物医学科学的职业生涯。

DESCRIPTION (provided by applicant): The leading causes of miscarriage and mental retardation in humans are chromosomal abnormalities, which can be generated by chromosome segregation errors during oocyte or sperm meiosis. The vast majority of de novo chromosomal structural abnormalities are of paternal origin; thus, it is vital to understand paternal chromosome segregation mechanisms to prevent both natural and assisted reproductive failure and the potential transmission of genetic diseases to offspring. We have identified the male-specific PP1 phosphatase homologs, GSP-3 and GSP-4, as the only known proteins with evolutionarily conserved function specifically in sperm formation from worms to humans. Our preliminary studies suggest that these phosphatases provide sex-specific regulation of chromosome orientation dynamics during the transition from meiosis I to meiosis II. GSP-3/4 localizes around sperm meiotic chromosomes in a pattern similar to that of kinetochore proteins, key connectors of chromosomes and microtubules. We also find GSP-3/4 regulate the sex-specific dynamic localization of specific kinetochore components. Thus, our hypothesis is that these PP1 phosphatases are key regulators of spindle microtubule attachment to chromatin and thus required for proper chromosome partitioning during sperm meiosis. We will test our hypothesis in three main areas: 1) chromosome orientation and microtubule dynamics during the MI to MII transition, 2) composition and dynamic localization of components of the kinetochore, and 3) localization of factors that modulate chromatin-microtubule interactions to orient chromosomes on the meiotic spindle. The proposed studies will identify molecular markers for sperm meiotic progression and paternal chromatin quality and content, which will further the fields of reproductive and developmental biology. Our team will also define the role of GSP-3/4 and key regulators of meiosis at specific stages of paternal chromosome segregation, making a significant contribution to the field of chromosome biology. This research will lay the groundwork for future development of clinical diagnostics and therapies to identify or prevent paternally-derived chromosomal abnormalities, a vital step to ensuring reproductive success and the health of future offspring. These studies will incorporate the diverse undergraduate and master's level students at SFSU, a historically minority-serving institution. We anticipate 2-3 students per year will conduct individual research projects using well-characterized reagents and assays with newly acquired cutting-edge equipment during the three-year award period. As such, they will gain hands-on, relevant research experience and critical thinking skills to further their careers in the biomedical sciences. PUBLIC HEALTH RELEVANCE: The leading causes of mental retardation and miscarriages in humans are chromosomal abnormalities generated during either oocyte or sperm meiosis. Determining the molecular mechanisms that govern paternal meiotic chromosome segregation is thus crucial to understanding how miscarriage, infertility, and birth defects like Down's Syndrome arise. This study will contribute to the eliminating a considerable gap in knowledge in how meiotic chromosome segregation is regulated in sex-specific ways to ensure reproductive and developmental success.