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：制造精子，精子是男性生殖系DNA不朽的载体；并产生激素，指导身体其他部位以男性特有的方式发育。Dmrt1属于保守转录调控家族，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：人类DMRT1的缺失与男性到女性的性别逆转、性别分化障碍（DSD）、不育症和睾丸生殖细胞肿瘤（tgct）有关。在小鼠中，Dmrt1控制胎儿性腺的生殖细胞多能性，并控制成人有丝分裂/减数分裂的决定。一项新的发现是Dmrt1必须在出生后积极地维持睾丸决定，并且Dmrt1突变的睾丸经过大量的出生后重编程成为卵巢样器官。该提案有三个目的，重点是加深我们对DMRT1如何控制睾丸关键过程的理解。目的1询问DMRT1如何阻止出生后睾丸的转分化。这是一个新发现的尚未研究的生物过程。这些实验使用条件基因靶向方法来研究DMRT1是否会阻止出生后胎儿性别决定网络的再激活，确定出生后性别维持的新调控因子，并使用ChIP-seq来识别小鼠和人类睾丸中DMRT1结合的基因。Aim 2使用精确控制的功能丧失和获得方法，验证了DMRT1对于从精原细胞干细胞到承诺祖细胞的转变至关重要的假设。目的3将确定当精原细胞从有丝分裂过渡到减数分裂时，DMRT1是如何失活的，并将测试这种情况发生时的后果。这项研究的结果将有助于治疗性腺癌和不育症，并将为细胞命运重编程和新型男性避孕药设计的研究提供信息。

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.