Oogenesis, Spematogenesis and Sperm -Egg Interactions

描述（由申请人提供）：两性配子是高度特化的细胞，具有将单倍体亲本基因组和早期胚胎发育所需因子传递给后代的独特功能。鉴定配子中特异性表达的基因产物是理解配子“转录组”功能的关键一步。我们使用了几种基因鉴定策略，包括退化PCR、硅减法、基于PCR的减法、基因组数据库挖掘和GeneChip技术来表征20多种新的性腺表达基因。在之前的U54中心资助期间，我们鉴定了小鼠和人类的Bmp15基因，并表明这些基因是x连锁的，并在卵母细胞中特异性表达。我们还发现敲除小鼠中的Bmp15会导致雌性生育缺陷，并且Bmp15和GDF9在排卵期具有协同作用。在目前的提案中，我们将重点关注我们小组发现的三个新的性腺特异性基因（Gasz， Tex14和Tektin3）。我们选择了这三个基因，因为它们在生殖细胞中特异性表达，是进化保守的

Description (provided by applicant): Gametes of both sexes are highly specialized cells with the unique function of transmitting haploid parental genomes and factors required for early embryonic development to the subsequent generation. Identifying gene products specifically expressed in gametes is a key step to understanding the functions of the gamete "transcriptome." We have used several gene identification strategies including degenerate PCR, in silico subtraction, PCR-based subtraction, genome database mining, and GeneChip technology to characterize over 20 novel gonad-expressed genes. During the previous U54 Center grant period, we identified the mouse and human Bmp15 genes and showed that these genes are X-linked and expressed specifically in oocytes. We also showed that a knockout of Bmp15 in mice results in female fertility defects and that BMP15 and GDF9 have synergistic roles in the periovulatory period. In the present proposal, we will focus on three novel gonad-specific genes (Gasz, Tex14, and Tektin3) that our group has identified. We selected these three genes because they are specifically expressed in germ cells, are evolutionarily-conserved in multiple vertebrate species including fish, frogs, mice, rats, and humans, and are hypothesized to play key roles regulating meiosis or sperm motility. To determine the roles of these three genes in development and the processes that control fertility in humans, we will define their biochemical and physiological properties using yeast two-hybrid screens and the generation of knockout mouse models. Together, the abilities to discover novel genes and define their functions in mouse models provide powerful means to study the molecular mechanisms of mammalian gametogenesis and enable us to place these gene products in biological pathways. Importantly, we can translate these findings to the problem of human infertility by identifying causative mutations. The specific aims of these proposed studies are as follows: 1) Characterize the functions of GASZ as a cytoplasmic signaling protein during male and female germ cell meiosis; 2) Study the ability of TEX14 to regulate key phosphorylation events during male meiosis; and 3) Define the functions of TEKTIN3 in sperm motility and male infertility by analysis of mice and humans with deletions and duplications of the chromosomal region encompassing the TEKTIN3 gene. These studies should give us greater insights into the roles of these proteins in germ cell biology. Compromised fertility in knockout models lacking these proteins would demonstrate that these proteins are potential contraceptive targets and possibly mutated in infertile men and women.