Cellular Signals in Ovulation and Luteinization

描述（由申请人提供）：排卵是哺乳动物繁殖的必要条件。这是一个复杂的炎症样过程，仅在成熟卵泡暴露于促黄体生成素（LH）激增时发生，并依赖于特定基因的LH诱导。这些鉴定是黄体酮受体（PR），分泌的金属蛋白酶ADAMTS-4和透明质子结合，基质相关蛋白多糖。排卵也依赖于几种PR调节基因，因为即使补充了外源激素，缺乏两种PR亚型（PRKO）的小鼠也不能排卵（不育）。PR靶基因包括其他分泌的金属蛋白酶ADAMTS-1和ADAM8，以及Wnt/Frizzled信号级联中的g蛋白偶联受体frzzled -1 （FZ-1）。与PRKO小鼠一样，ADAMTS-1缺失小鼠具有不育性，表明该金属蛋白酶介导了LH和PR在排卵中的作用。由于LH诱导PR的分子机制以及PR如何影响ADAMTS-1的表达似乎涉及这两个基因近端启动子中关键的Spl/Sp3结合位点，因此我们建议确定与Spl/Sp3相互作用以控制转录的关键调控因子。我们建议进一步确定结构和功能相关的金属蛋白酶ADAMTS-1和ADAMTS-4（以及ADAM8）影响排卵的机制。我们假设这些蛋白酶影响

Description (provided by applicant): Ovulation is essential for mammalian reproduction. It is a complex inflammation-like process that occurs only when mature follicles are exposed to the luteinizing hormone (LH) surge and is dependent on LH induction of specific genes. Those identified are the progesterone receptor (PR), the secreted metalloproteinase ADAMTS-4 and the hyaluronon binding, matrix associated proteoglycan versican. Ovulation is also dependent on several PR-regulated genes since mice null for both PR subtypes (PRKO) fail to ovulate (are infertile) even when supplemented with exogenous hormones. PR target genes include other secreted metalloproteinases ADAMTS-1 and ADAM8, as well as the G-protein coupled receptor Frizzled-1 (FZ-1), a member of the Wnt/Frizzled signaling cascade. Like PRKO mice ADAMTS-1 null mice are infertile indicating this metalloproteinase mediates some effects of LH and PR in ovulation. Since the molecular mechanisms by which LH induces PR and how PR impacts expression of ADAMTS-1 appear to involve critical Spl/Sp3 binding sites in the proximal promoters of these two genes, we propose to determine the critical regulatory factors that interact with Spl/Sp3 to control transcription. We propose further to determine the mechanisms by which the structurally and functionally related metalloproteinases ADAMTS-1 and ADAMTS-4 (as well as ADAM8) impact ovulation. We hypothesize that these proteinases impact the formation and function of the extracellular matrix (ECM) that is made during cumulus oocyte expansion, which is essential for extrusion of the ooctye from the ovulation pore and its uptake by the oviduct. This hypothesis is based on the evidence that versican, ADAMTS-1 and ADAMTS-4 are made by cumulus cells, co-localize in the matrix and that versican is a preferred substrate for these enzymes. Lastly, we propose that ovulation is dependent on the induction of Fz-1, a G-protein coupled receptor that mediates beta-catenin signaling and gene expression. Using new molecular approaches for analyzing factors that regulate gene activation (ChIP, DAPA and siRNA), as well as mutant mouse models that permit conditional disruption of target genes in granulosa cells, we propose to: I) Determine the molecular mechanisms by which LH induces expression of ovulation-related genes, PR and ADAMTS- 1; II) Determine the functional roles of LH and PR induced genes ADAMTS-1, ADAMTS-4 and Fz-1 in ovulation; III) Identify novel LH and PR regulated genes that impact ovulation. These studies should provide novel information about the hormonal regulation of PR and its target genes in the ovulation process and lead to new insights into causes of infertility in women as well as to new methods of contraception.