Opposing Pathways in Mammalian Sex Determination

哺乳动物性别决定的相反途径

• 批准号: 9042693
• 负责人: Blanche Capel
• 金额: $ 38.27万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-18 至 2021-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9042693
• 关键词: Cell Cycle; Cell Cycle Arrest; Cell Lineage; Cell division; Cells; Chemicals; Complex; Cyclin-Dependent Kinase Inhibitor; Data; Development; Embryo; Epigenetic Process; Equilibrium; FOXL2 gene; Female; Funding; GATA4 gene; Genes; Genomics; Gonadal structure; Human; Infertility; Link; Mediating; Mus; Mutation; Organ; Organogenesis; Ovarian; Ovarian Follicle; Ovary; PRC1 Protein; Pathology; Pathway interactions; Phenotype; Play; Polycomb; Process; Proteins; Repression; Reproductive Biology; Role; Sexual Development; Signal Transduction; Staging; Supporting Cell; Testing; Testis; base; cell fate specification; cell type; chromatin remodeling; conditional mutant; gene repression; granulosa cell; insight; intercellular communication; loss of function; male; notch protein; polycomb-M33; progenitor; sex; sex determination; sex development disorder; sry Genes; stem cell biology; transcriptome

DESCRIPTION (provided by applicant): Pathologies of sexual development are common in humans, reflecting the precarious processes of sex determination and sexual differentiation. The gonad forms as a bipotential organ, composed of cells that can differentiate as testis or ovarian cell types. The primary sex-determining step is the fate decision that occurs in the somatic supporting cell lineage. We previously showed that supporting cells are initially balanced between Sertoli (testis) and follicle (ovary) fates by opposing and antagonistic signaling networks. In XY embryos, this balance is disrupted by the transient expression of the Y-linked gene Sry in supporting cell precursors. Our global analysis of the gonad transcriptome revealed two concurrent networks in the XY bipotential gonad, one male and one female. This data suggests that male sex determination requires both the activation of male pathway genes and the stable repression of the underlying female pathway during male fate determination. This idea is supported by the finding that loss of function of the polycomb protein M33/CBX2 in mice or humans results in male to female sex reversal. During this funding period, we found that Notch signals in rapidly dividing cells that give rise to the supporting cell precursors, whereas NUMB localizes basolaterally in these cells, but is symmetrically distributed in cells in the interior of the gonad that establish expression of either SRY and its downstream target SOX9, or the earliest marker of female supporting cell precursors, FOXL2. We found that NUMB-expressing supporting cell precursors of both sexes are p27/p21-positive and arrested in G0/G1 of the cell cycle at the stage when differentiation begins. We hypothesize that Numb mediates cell cycle arrest, which is required for chromatin remodeling through the activity of the polycomb complex (PRC1) to establish and/or maintain Sertoli and granulosa cell fate. In this proposal, we will determine how gonadal cells approach and execute the sex-determining cell fate decision through the following aims: (1) Determine the role of Notch/Numb signaling and cell cycle arrest in specification of the supporting cell lineage; (2) Determine whether M33/PRC1 is required to establish the supporting cell lineage and to maintain Sertoli or granulosa cell fate. Integration of the cell cycle with cell fate specification and epigenetic reprogramming will have broad relevance to the fields of organogenesis and stem cell biology and will provide insight into the developmental basis for disorders of sexual development and infertility.

描述（由申请人提供）：性发育的病理在人类中很常见，反映了性别决定和性别分化的不稳定过程。性腺是一个双能器官，由可以分化为睾丸或卵巢细胞类型的细胞组成。主要的性别决定步骤是发生在体细胞支持细胞谱系中的命运决定。我们以前表明，支持细胞最初是通过对立和拮抗信号网络在支持细胞（睾丸）和卵泡（卵巢）之间平衡的。在XY胚胎中，这种平衡被支持细胞前体中Y连锁基因Sry的瞬时表达所破坏。我们对性腺转录组的全球分析揭示了XY双能性腺中的两个并发网络，一个男性和一个女性。这一数据表明，男性性别决定需要男性途径基因的激活和稳定的镇压的基础女性途径在男性的命运决定。这一想法得到了以下发现的支持，即小鼠或人类中多梳蛋白M33/CBX 2的功能丧失导致雄性到雌性的性别逆转。在此资助期间，我们发现Notch信号在快速分裂的细胞中产生支持细胞前体，而NUMB定位于这些细胞的基底外侧，但对称分布在性腺内部的细胞中，这些细胞表达SRY及其下游靶点SOX 9，或雌性支持细胞前体的最早标志物FOXL 2。我们发现，NUMB表达的支持细胞前体的两种性别是p27/p21阳性和停滞在G 0/G1期的细胞周期的阶段时，分化开始。我们假设Numb介导细胞周期停滞，这是通过polycomb复合物（PRC 1）的活性来建立和/或维持支持细胞和颗粒细胞命运的染色质重塑所必需的。在本研究中，我们将通过以下目的确定性腺细胞如何接近和执行性别决定细胞命运决定：（1）确定Notch/Numb信号传导和细胞周期阻滞在支持细胞谱系特化中的作用;（2）确定M33/PRC 1是否需要建立支持细胞谱系并维持支持细胞或颗粒细胞命运。整合细胞周期与细胞命运的规范和表观遗传重编程将有广泛的相关性，器官发生和干细胞生物学领域，并将提供洞察性发育障碍和不育症的发展基础。