Transcriptional Regulation of Early Folliculogenesis

描述（由申请人提供）：卵子发生是卵巢发育、胚胎发生和体内平衡所必需的一个特化和受调控的过程。这一通路的调节和结构组分的病理变化影响卵巢分化、维持和早期胚胎发生。对卵子发生中重要的生物调节剂的基本了解，特别是那些在转录水平上起作用的生物调节剂，将进一步加深我们对卵母细胞生物学的理解，并提供对病理过程的深入了解，包括卵巢早衰、生殖寿命、绝经、卵巢肿瘤和早期胚胎丢失。识别和鉴定在卵母细胞中优先表达的基因将非常有助于揭示它们在卵母细胞中的特异性功能及其对卵巢病理学的贡献。我们利用来自新生儿卵巢文库的表达序列标签（EST）的电子减法，发现了一个新的同源框基因，我们称之为Nobox，该基因优先在原始卵泡和生长中的卵母细胞中表达。Nobox在卵泡发育早期表达，可能在哺乳动物卵子发生中起重要作用。为了进一步研究Nobox在卵巢发育中的作用，我们使用同源重组的基因靶向产生了Nobox突变等位基因纯合的小鼠。Nobox缺陷小鼠的卵巢可以形成原始卵泡，但不能生长，到6周龄时很小，缺乏可辨别的卵泡和卵母细胞。这些卵巢的组织学非常类似于无滤泡型非综合征性卵巢早衰妇女的卵巢。我们建议研究细胞和分子机制，阻止卵泡发育，并导致加速损失的卵母细胞在Nobox -/-卵巢。我们将描述NOBOX DNA结合位点的特征，并识别由NOBOX直接和间接调控的基因。我们还建议识别和分析与NOBOX相互作用的蛋白质。这些研究将有助于增加描述卵母细胞特异性遗传途径的信息量，并有助于我们理解编码这些途径的基因突变的病理后果。

DESCRIPTION (provided by applicant): Oogenesis is a specialized and regulated process essential for ovarian development, embryogenesis and homeostasis. Pathologic changes in both regulatory and structural components of this pathway affect ovarian differentiation, maintenance, and early embryogenesis. A basic understanding of the biologic modifiers important in oogenesis, especially those, which act on the transcriptional level, would further our understanding of oocyte biology as well as provide insight into pathologic processes including premature ovarian failure, reproductive life span, menopause, ovarian tumors and early embryonic losses. Identification and characterization of genes preferentially expressed in oocytes will be extremely useful in unraveling their oocyte-specific functions and their contribution to ovarian pathology. We utilized in silico subtraction of expressed sequence tags (ESTs) derived from newborn ovary library to discover a novel homeobox gene preferentially expressed in primordial follicles and growing oocytes, which we call Nobox. Nobox is expressed early in folliculogenesis and may play important roles in regulating mammalian oogenesis. To further study the role of Nobox in ovarian development we generated mice homozygous for the Nobox mutant allele using gene targeting by homologous recombination. Ovaries from mice deficient in Nobox can form primordial follicles but fail to grow and by 6 weeks of age are small and lack discernable follicles and oocytes. The histology of these ovaries closely resembles ovaries from women with afollicular type of non-syndromic premature ovarian failure. We propose to study cellular and molecular mechanisms that block follicular development and cause accelerated loss of oocytes in Nobox -/- ovaries. We will characterize NOBOX DNA binding sites and identify genes regulated directly and indirectly by Nobox. We also propose to identify and analyze proteins that interact with NOBOX. These studies will help add to the rapidly increasing amount of information delineating oocyte-specific genetic pathways and to our understanding of the pathologic consequences of mutations in the genes that encode them.