Control of Multidrug Transport Activity in Embryos

这项研究的两个主要目标是，首先，了解多药流出的细胞生物学调节 其次，探讨这些转运蛋白在胚胎保护和调节中的作用。 发展。这一提议连接了两个知识体系，一个是关于细胞生理学的 多药外排转运，主要在癌症和上皮转运的背景下进行检查，以及另一个 重点关注胚胎发育过程中细胞表面和膜组织的结构变化。在 在本提案的原产地规则阶段，哈姆杜恩将继续并扩大对两者之间关系的调查 早期胚胎发育中的细胞表面变化和外排转运蛋白活性的变化侧重于 海胆是一种易于分析和操作的模式生物。他也将继续努力，目前 该奖项的 K 阶段正在进行中，将海胆的研究结果转化为小鼠模型，以便 表征这些活性变化在保护胚胎免受潜在致畸因素影响方面的作用 辅助生殖过程中遇到的。该奖项 K 阶段的研究揭示了快速上调 海胆卵受精后 ABCB (pgp) 和 ABCC (mrp) 外排转运蛋白活性的变化 然后在 4 个胚胎生殖系祖细胞的子集中下调外排运输，已知 作为小微米。在大多数其他系统中，ABC转运蛋白进出膜的循环是连续的，而在海胆中，外排活动和皮质组织的两次快速变化为研究细胞结构和转运蛋白功能关系提供了强大的模型。在目标 1 和 2 中，Hamdoun 将通过转运蛋白移动到微绒毛尖端来表征 Sp-ABCB1a（哺乳动物 p-gp 的直系同源物）活性的受精后重新分配。在第三个目标中，Hamdoun 将把这些发现扩展到小鼠模型，特别是在小鼠卵母细胞受精后 pgp 转运蛋白活性丧失的初步发现之后，他将再次关注活性变化如何与皮质肌动蛋白细胞骨架的组织相关。在新的第四个目标中，哈姆杜恩将研究小微粒中转运蛋白的调节机制。

The two main goals of this research are first, to understand the cell biological regulation of multidrug efflux transport and second, to probe the roles of these transporters in protection and regulation of embryonic development. This proposal links between two bodies of knowledge, one on the cellular physiology of multidrug efflux transport, primarily examined in the context of cancer and epithelial transport, and another focusing the structural changes in cell surface and membrane organization of embryo development. In the ROO Phase of this proposal, Hamdoun will continue and expand his investigation ofthe relationship between cell surface changes in early embryo development and changes in the efflux transporter activity focusing on sea urchins as an easily assayed and manipulated model organism. He will also continue efforts, currently ongoing in the K Phase of this award, to translate findings from the sea urchin to the mouse model, in order to characterize the role of these activity changes in protection of the embryo from potential teratogens encountered during assisted reproduction. Research in the K Phase of this award has revealed rapid upregulation of ABCB (pgp) and ABCC (mrp) efflux transporter activity following fertilization of sea urchin eggs and then later down-regualtion of efflux transport In a subset of 4 embryonic germline progenitor cells, known as the small micromeres. In most other systems, cycling of ABC transporters in and out of membranes is continuous, whereas in the sea urchin the two episodes of rapid change in efflux activity and cortical organization provide a powerful model for studying the cell structure and transporter function relationships. In Aims 1 and 2 Hamdoun will characterize the post-fertilization redistribution of Sp-ABCB1a (an ortholog of mammalian p-gp) activity by movement of the transporter to the tips of microvilli. In the third Aim, Hamdoun will extend these findings to the mouse model, specifically following up on his preliminary finding of loss of pgp transporter activity after fertilization of mouse oocytes and again he will focus on how activity changes relate to organization ofthe cortical actin cytoskeleton. In a new fourth Aim, Hamdoun will study the mechansims of transporter regulation in the small micromeres.