Regulation of Spermatogenesis by X-linked miRNAs

X 连锁 miRNA 对精子发生的调节

• 批准号: 7889745
• 负责人: John R MCCARREY
• 金额: $ 40.76万
• 依托单位: UNIVERSITY OF NEVADA RENO
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-01 至 2015-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7889745
• 关键词: Accounting; Active Sites; Cell Nucleus; Cell physiology; Cells; Characteristics; Collaborations; Contraceptive Agents; Cytoplasm; DNA; Data; Defect; Development; Diagnosis; Embryo; Employee Strikes; Euchromatin; Female; Fertility; Functional RNA; Gene Cluster; Gene Silencing; Genes; Germ; Germ Cells; Grant; Hormonal; In Vitro; Knock-out; Lead; Link; Male Infertility; Mediating; Meiosis; Messenger RNA; MicroRNAs; Molecular; Molecular Genetics; Molecular Profiling; Mus; National Institute of Child Health and Human Development; Nuclear; Organ; Pattern; Phase; Physical condensation; Play; Post-Transcriptional Regulation; Process; Production; Prophase; Proteins; Regulation; Reporting; Role; Sex Chromosomes; Somatic Cell; Spermatocytes; Spermatogenesis; Spermiogenesis; Staging; Structural Genes; Technology; Testing; Testis; Translating; X Chromosome; X Inactivation; Y Chromosome; blastomere structure; chromatin modification; design; gene repression; homologous recombination; in vivo; insight; knockout gene; mRNA Stability; male; mammalian genome; mutant; novel; public health relevance; sex; sperm cell

DESCRIPTION (provided by applicant): Meiotic sex chromosome inactivation (MSCI) during spermatogenesis is characterized by transcriptional silencing of genes on both the X and Y chromosomes in mid to late pachytene spermatocytes. MSCI is believed to result from meiotic silencing of unpaired DNA because the X and Y chromosomes remain largely unpaired throughout first meiotic prophase. Thus, unlike X-chromosome inactivation in female embryonic or somatic cells, where 25-30% of X-linked structural genes have been reported to escape inactivation, there have been no previous reports of genes that escape the silencing effects of MSCI in primary spermatocytes. However, we recently discovered that many X-linked microRNAs (miRNAs) are transcribed and processed in pachytene spermatocytes. This unprecedented escape from MSCI suggests that these miRNAs participate in one or more critical functions at this stage of spermatogenesis. This is corroborated by our preliminary finding that chimeric mice carrying a high percentage of cells bearing a knockout of a major cluster of X-linked miRNA genes display a fertility defect manifest as a block during the meiotic phase of spermatogenesis. This is significant because despite recent reports describing expression of an abundance of miRNAs and other small, non-coding RNAs during spermatogenesis, essentially nothing is known about the function of any of these. In this application, we first propose to investigate the molecular mechanism by which these X-linked miRNA genes escape MSCI (Aim 1). We then propose to test two hypotheses (which are not mutually exclusive) regarding function of these miRNAs, including their role as post- transcriptional regulators of autosomal mRNAs that are synthesized during meiosis but not translated until the postmeiotic period (Aim 2), and their role in regulating the process of MSCI itself (Aim 3). This study is highly novel in that it is designed to reveal an unprecedented mechanism of escape from MSCI, and to identify actual functions of those X-linked miRNAs that undergo this escape during spermatogenesis. PUBLIC HEALTH RELEVANCE: Understanding the molecular and genetic mechanisms by which sperm are produced is critically important for diagnosis and treatment of male infertility, as well as for the development of non-hormonal male-specific contraceptives. Data from the present study will contribute insight into the function of X-linked miRNAs in the control of sperm production and male fertility.

描述（由申请人提供）：精子发生过程中的减数分裂性染色体灭活（MSCI）的特征是在pachytene精子细胞中期至晚期的X和Y染色体上基因的转录沉默。据信MSCI是由于未配对DNA的减数分裂沉默而导致的，因为X和Y染色体在整个首次减数分裂预言中基本上仍然不属于不足。因此，与雌性胚胎或体细胞中的X染色体灭活不同，据报道，据报道，有25-30％的X连锁结构基因避免了灭活，也没有关于基因逃避原代精子细胞中MSCI的沉默的报道。但是，我们最近发现，许多X连锁的microRNA（miRNA）在pachytene精子细胞中被转录和处理。从MSCI逃脱的这种前所未有的逃脱表明，这些miRNA在精子发生阶段参与了一个或多个关键功能。我们的初步发现证实了这一点，即携带高比例的细胞的嵌合小鼠在X线连接的主要基因中敲除，在精子发生的减数分裂阶段表现出生育能力缺陷表现为块。这很重要，因为尽管最近有报道描述了精子发生过程中丰富的miRNA和其他小型非编码RNA的表达，但基本上对这些功能的功能一无所知。在此应用中，我们首先建议研究这些X连锁miRNA基因逃脱MSCI的分子机制（AIM 1）。然后，我们建议对这些miRNA的功能进行两个假设（不是相互排斥的），包括它们作为常染色体mRNA的转录后调节剂的作用，它们在减数分裂过程中合成，但直到寿位元期（AIM 2）及其在调节MSCI本身中的作用（aim 2），尚未翻译（AIM 2）（目标3）。这项研究很新颖，因为它旨在揭示从MSCI逃脱的前所未有的机制，并确定那些在精子发生过程中经历这种逃逸的X连锁miRNA的实际功能。 公共卫生相关性：了解产生精子的分子和遗传机制对于诊断和治疗男性不育以及非荷尔蒙男性特异性避孕药的发展至关重要。本研究的数据将有助于深入了解X连锁miRNA在控制精子产生和男性生育方面的功能。