DMRT1 in mammalian sexual development

描述(由申请人提供)：拟议工作的总体目标是了解DMRT1基因如何控制睾丸的发育和功能。睾丸有两个基本功能：产生精子，即作为雄性生殖系DNA永生载体的细胞；以及产生荷尔蒙，引导身体其他部位以男性特有的方式发育。DMRT1属于一个保守的转录调控家族，控制着哺乳动物睾丸的多个关键过程。这项工作与人类健康直接相关：在人类中，DMRT1的缺失与男性到女性的性别逆转、性分化障碍(DSD)、不育症和睾丸生殖细胞肿瘤(TGCT)有关。在小鼠中，DMRT1控制胎儿性腺中生殖细胞的多能性，并控制成人的有丝分裂/减数分裂决定。一项新的发现是，睾丸的决定必须在出生后由DMRT1主动维持，DMRT1突变的睾丸在出生后经历大量的重新编程，才能成为卵巢样器官。这项提案有三个目标，旨在加深我们对DMRT1如何控制睾丸关键过程的理解。目的1问DMRT1如何阻止出生后睾丸的转分化。这是一个新发现的、未被研究的生物过程。拟议的实验使用条件性基因打靶方法来询问DMRT1是否可以阻止出生后胎儿性别决定网络的重新激活，识别出生后性别维持的新调节因素，并使用CHIP-SEQ来识别小鼠和人类睾丸中与DMRT1结合的基因。目的2利用精确控制的功能丧失和功能获得的方法，检验DMRT1对于精原干细胞向承诺的祖细胞的转变至关重要的假设。目标3将确定DMRT1是如何在精原细胞从有丝分裂向减数分裂转变时失活的，并将测试当这一过程未能发生时的后果。这项研究的结果将有助于性腺癌和不育症的治疗，并将为细胞命运重新编程和设计新型男性避孕药的研究提供参考。

DESCRIPTION (provided by applicant): The overall objective of the proposed work is to understand how the Dmrt1 gene controls development and function of the testis. The testis has two essential functions: production of sperm, the cells that serve as vehicles for the immortality of male germ line DNA; and production of hormones that direct other parts of the body to develop in a male-specific manner. Dmrt1 belongs to family of conserved transcriptional regulators and controls multiple critical processes in the mammalian testis. This work has direct human health relevance: loss of DMRT1 in humans is associated with male-to-female sex reversal, disorders of sexual differentiation (DSD), infertility, and testicular germ cell tumors (TGCTs). In mice Dmrt1 controls germ cell pluripotency in the fetal gonad and controls the mitosis/meiosis decision in adults. A new discovery is that testis determination must be actively maintained postnatally by Dmrt1 and that Dmrt1 mutant testes undergo massive postnatal reprogramming to become ovary-like organs. This proposal has three aims focused on deepening our understanding of how DMRT1 controls key processes in the testis. Aim 1 asks how DMRT1 prevents transdifferentiation in the postnatal testis. This is a newly discovered and unstudied biological process. The proposed experiments use conditional gene targeting approaches to ask whether DMRT1 prevents reactivation of the fetal sex determination network postnatally, identify new regulators of postnatal sex maintenance, and use ChIP-seq to identify genes that are bound by DMRT1 in the mouse and human testis. Aim 2 tests the hypothesis that DMRT1 is critical for the transition from spermatogonia stem cell to committed progenitor cell, using precisely controlled loss- and gain-of-function approaches. Aim 3 will determine how DMRT1 is inactivated as spermatogonia transition from mitosis to meiosis and will test the consequences when this fails to occur. The results of this study should aid in treatment of gonadal cancer and infertility, and will inform studies of cell fate reprogramming and design of novel male contraceptives.