Transition Metal Regulation of Oocyte Maturation

本研究的目的是了解锌在控制卵母细胞成熟中的作用。 锌是生物系统中使用最广泛的金属之一，是数百种重要的辅助因子， 转录因子、磷酸酶、激酶和金属酶。锌稳态的管理是 在哺乳动物基因组中，锌特异性转运蛋白受到严格调控，并且超过20种锌特异性转运蛋白是保守的。 其中三种锌转运蛋白在小鼠卵母细胞和受精卵中高度富集 超过60种其他组织。我们的初步研究结果表明，三个生理过程可能 依赖于锌作为特定的调节因子。使用锌特异性荧光团，我们已经确定了 颗粒细胞作为游离锌的来源，并预测锌通过锌转运到卵母细胞 在卵泡发育过程中，存在于连接这两个细胞的跨带投射中的转运蛋白 发展其次，在卵母细胞体外成熟过程中去除锌会阻断卵母细胞的扩增。 并导致卵母细胞的对称胞质分裂，而不是不对称的极性 身体挤压这些表型被外源锌拯救。最后，将锌输送到减数分裂 成熟的卵导致孤雌生殖激活。这些研究表明了一种以前未被认识到的联系 锌依赖性信号通路和卵母细胞成熟之间的关系，并且是本申请的焦点。 我们的总体假设是，卵母细胞在卵泡中完成成熟并过渡到一个 有减数分裂能力的卵依赖于锌的调节和卵母细胞富集的锌特异性受体。这 一个高度跨学科的团队在三个相互关联的实验目标中解决了假设， 生殖科学、化学生物学和生物物理学。虽然现象学证据 这一建议强烈支持锌在卵母细胞功能中的调节作用，生化机制只是 开始出现在文献和我们自己的初步数据中。研究结果建议， 该项目将为卵母细胞发育提供一种创新的新模式，并为卵母细胞发育研究增添新成员。 无机信号分子家族（如Ca2+、NO、O2和CO2），其控制基本细胞 和发展过程。

The objective of this research proposal is to understand the role of zinc in the control of oocyte maturation. Zinc is one of the most widely utilized metals in biological systems and is an essential co-factor in hundreds of transcription factors, phosphatases, kinases, and metalloenzymes. Management of zinc homeostasis is tightly regulated and over twenty zinc-specific transporters are conserved across mammalian genomes. Three of these zinc-transporting proteins are highly enriched in the mouse oocyte and fertilized egg relative to more than 60 other tissues. Our preliminary findings suggest that three physiological processes may depend on zinc as a specific regulatory factor. Using zinc-specific fluorophores, we have identified the granulosa cells as a source of free zinc and predict that zinc is transported to the oocyte through zinc transport proteins present in the transzonal projections connecting these two cells during follicle development. Secondly, removal of zinc during in vitro maturation of oocytes blocks expansion of the surrounding cumulus cells and causes symmetric cytokinesis of the oocyte rather than asymmetric polar body extrusion. These phenotypes are rescued by exogenous zinc. Finally, delivery of zinc to meiotically mature eggs results in parthenogenic activation. These studies suggest a previously unrecognized link between zinc-dependent signaling pathways and oocyte maturation and are the focus of this application. Our overall hypothesis is that the completion of oocyte maturation in the follicle and transition to a meiotically competent egg depends on zinc regulation and oocyte-enriched zinc-specific receptors. This hypothesis is addressed in three interiinked experimental aims by a highly interdisciplinary team that bridges reproductive science, chemical biology and biophysics. While the phenomenological evidence underlying the proposal strongly supports a regulatory role for zinc in oocyte function, biochemical mechanisms are just beginning to emerge in the literature and from our own preliminary data. The results of studies proposed by this project will provide an innovative new model for oocyte development, and add new member(s) to the family of inorganic signaling molecules (such as Ca2+, NO, 02, and C02) that control fundamental cellular and developmental processes.