PROTO-ONCOGENES IN GAMETOGENESIS AND EARLY DEVELOPMENT

该项目的总体目标是了解原生生物的作用。 哺乳动物胚胎配子发生和早期发育中的癌基因。 这项拟议中的研究集中在调节 C-mos基因的转录，它在减数分裂中起着关键作用 脊椎动物卵母细胞。C-mos的转录受到严格的 组织特异性调控，导致其在男性中的特异性表达 和雌性生殖细胞。对c-mos的这种监管不仅是为了 在生殖细胞中实现适当的c-mos表达，同时也防止 在体细胞中不适当的表达，这可能导致 细胞死亡或肿瘤转化。同样值得注意的是，c- 在胚胎发育早期，MOS的表达下调，这可能是 防止胚胎卵裂分裂受阻所必需的 MOS作为一种细胞抑制因子的作用。 C-mos在体细胞中的转录被负性抑制 C-mos启动子上游的调控元件(NRE)。此外, 最近的研究已经确定了一种候选的体细胞抑制因子 与c-mos NRE内的功能元件结合。我们现在计划 克隆阻遏蛋白基因并对其进行鉴定 抑制c-mos转录的作用机制，并可能 其他生殖细胞特异性基因，在体细胞中。 C-mos在卵母细胞中的表达，不受NRE的影响， 只需要一个最小的启动子，包括一个启动子(INR)元件。 这些发现表明，在卵母细胞中c-mos转录 由高水平的基础转录活性产生，然后 在两细胞胚胎中被抑制。这将由进一步的调查 C-mos INR基因转录调控活性的研究 卵母细胞和胚胎，以及表达和分析 C-mos抑制因子在胚胎发育中的作用。 拟议的研究有三个具体目标： 1.体细胞基因克隆的分离与鉴定 C-mos转录抑制因子。 2.C-MOS的结构/功能分析及作用机理研究 抑制者行动。 3.卵母细胞中c-mos转录调控的研究 和早期胚胎。

The overall goal of the project is understanding the roles of proto- oncogenes in gametogenesis and early development of mammalian embryos. The proposed research is focused on the mechanisms that regulate transcription of the c-mos gene, which plays a critical role in meiosis of vertebrate oocytes. Transcription of c-mos is subject to stringent tissue--specific regulation, leading to its specific expression in male and female germ cells. Such regulation of c-mos is needed not only to achieve appropriate c-mos expression in germ cells but also to prevent inappropriate expression in somatic cells, which can result in either cell death or neoplastic transformation. It is also noteworthy that c- mos expression is downregulated early in embryogenesis, which may be necessary to prevent arrest of embryonic cleavage divisions resulting from the action of Mos as a cytostatic factor. Transcription of c-mos in somatic cells is suppressed by a negative regulatory element (NRE) upstream of the c-mos promoter. In addition, recent studies have identified a candidate somatic cell repressor that binds to a functional element within the c-mos NRE. We now plan to isolate a cDNA clone of the repressor protein and to characterize its mechanism of action in suppressing transcription of c-mos, and possibly other germ cell-specific genes, in somatic cells. Expression of c-mos in oocytes, which is not affected by the NRE, requires only a minimal promoter, including an initiator (Inr) element. These findings suggest the hypothesis that c-mos transcription in oocytes results from a high level of basal transcription activity, which is then suppressed in two-cell embryos. This will be investigated by further studies of the activity of the c-mos Inr in directing transcription in oocytes and embryos, together with analysis of the expression and function of the c-mos repressor during embryonic development. The proposed studies have three specific aims: 1. Isolation and characterization of a cDNA clone for a somatic cell repressor of c-mos transcription. 2. Structure/function analysis and studies of the mechanism of c-mos repressor action. 3. Investigation of the regulation of c-mos transcription in oocytes and early embryos.