DMRT1 in Mammalian Sexual Development

描述(申请人提供)：我们鉴定了第一类广泛保守的性调节基因，即与果蝇双性基因相关的转录因子。它们共享一个独特的锌指DNA结合域，我们称之为DM结构域。在当前的资金周期中，我们研究了DMRT1的功能，DMRT1是该基因家族中的一个哺乳动物成员。人DMRT1定位于9p染色体上的一段短片段，该片段在睾丸发育不全中缺失。我们发现，小鼠DMRT1的零突变会导致睾丸分化的严重缺陷，并在至少一个品系背景下导致性别反转。我们在其他物种中的表达研究表明，DMRT1可能是所有脊椎动物睾丸发育所必需的，包括那些具有高度分化的性别决定机制的脊椎动物。 我们提出的工作的目的是阐明DMRT1和两个相关基因在遗传和分子水平上控制哺乳动物性腺发育的机制。我们有四个目标。在目标1中，我们调查了DMRT1在胚胎性腺中控制哪些已知的性调节基因。我们还将测试相关基因DMRT3的功能。DMRT3在胚胎睾丸中表达，其人类同源基因和DMRT1一样，受到性别逆转的人类9P缺失的影响。在目标2中，我们在睾丸中寻找DMRT1调节的额外靶点，并对直接调节的靶点进行测试。在目标3中，我们研究了DMRT1蛋白是如何控制转录的，测试了与DMRT1特异相互作用的候选转录辅助调节因子的功能重要性。在目标4中，我们研究了Dmrt5在性腺发育中的作用，Dmrt5是一种与DMRT1相关的卵巢特异基因，测试它在女性中是否起到类似于DMRT1在男性中的作用。我们的工作将有助于揭示哺乳动物性别分化的分子基础，并建立一条调控基因的途径。这也将促进我们在这一关键过程中对人类先天缺陷病因的理解。

DESCRIPTION (provided by applicant): We identified the first widely conserved class of sexual regulatory genes, transcription factors related to the Drosophila doublesex gene. These share a unique zinc finger DNA binding domain we named the DM domain. In the current funding cycle we have investigated the function of Dmrt1, a mammalian member of this gene family. Human DMRT1 maps to a short segment on chromosome 9p that is deleted in testis dysgenesis. We showed that a null mutation in murine Dmrt1 causes severe defects in testis differentiation and causes sex reversal on at least one strain background. Our expression studies in other species showed that Dmrt1 is probably required for testis development in all vertebrates, including those with highly diverged sex determination mechanisms. The objective of the work we propose is to elucidate the mechanisms by which Dmrt1 and two related genes control mammalian gonad development, at both the genetic and molecular levels. We have four aims. In Aim 1, we investigate which of the known sexual regulatory genes Dmrt1 controls in the embryonic gonad. We also will test the function of a related gene, Dmrt3. Dmrt3 is expressed in the embryonic testis and its human homologue, like DMRT1, is affected by sex reversing human 9p deletions. In Aim 2 we search for additional targets of Dmrt1 regulation in the testis, and test which are regulated directly. In Aim 3 we investigate how the Dmrt1 protein controls transcription, testing the functional importance of candidate transcriptional coregulators that specifically interact with Dmrt1. In Aim 4, we investigate the role in gonad development of Dmrt5, an ovary-specific gene related to Dmrt1, testing whether it plays a role in females analogous to that of Dmrt1 in males. Our work will help to reveal the molecular basis of mammalian sexual differentiation and to establish a pathway of regulatory genes. This will also advance our understanding of the etiology of human congenital defects in this critical process.