Dmrt1基因缺失造成雄性斑马鱼垂体细胞过度增殖的分子机制研究

The pituitary, which is the most important endocrine gland in vertebrates, can regulate growth, development, metabolism and reproduction by secreting hormones. There are six cell subsets controlling the secretion of hormone in the pituatary, and the differentiation and maintain of each cell subset are tightly controlled by multiple signaling pathways and transcription factors. Dmrt1 is a transcription factor with conserved functions during gonad development, but there is no study had reported its function in pituitary development. Our previous studies have shown that the male zebrafish with the dmrt1 deletion exhibited increasingly serious enlargement in the adenohypophysis. And, compared to the control, the expression of gonadotropin gene in mutant was significantly upregulated. We suppose that the deletion of dmrt1 can induce over-proliferation of gonadotropes in male zebrafish, and then leading to adenohypophysis enlargement. So, we carry out the following researches by using histology technology, CHIP-seq and RNA-seq analysis to confirm the expression of Dmrt1 in gonadotropes, verify the histological changes in gonadotropes subset after dmrt1 is knocked out, find the downstream target genes and signal pathways regulated by Dmrt1 in pituitary, and reveal the molecular mechanism of pituitary cells proliferation regulated by Dmrt1. The approval and implementation of this project will first illuminate the transcriptional regulation functions of Dmrt1 in pituitary development, and provide theoretical basis for the pathological mechanism study of pituitary adenomas.

垂体通过分泌激素调节机体的生长发育﹑生殖和代谢，为脊椎动物最重要的内分泌腺。垂体中负责激素产生的是六个内分泌细胞亚群，它们的分化和维持受到许多信号通路和转录因子的严格调控。Dmrt1是保守的性腺发育相关的转录因子，目前尚未有报道阐述其在垂体发育中的作用。而我们前期的研究发现，dmrt1基因敲除的雄性斑马鱼存在垂体异常膨大且程度日益加重的表型，同时其促性腺激素（GTH）基因的表达显著上调，推测雄鱼中Dmrt1的缺失引发GTH细胞亚群过度增殖，进而导致垂体膨大。鉴于此，本项目将通过组织学技术和组学方法展开研究，明确dmrt1基因在GTH细胞中的表达，证实Dmrt1缺失后GTH细胞亚群发生的改变，找到垂体中Dmrt1作用的靶基因和影响的信号通路，进而揭示Dmrt1调控垂体细胞增殖的分子机制。该项目的获准与实施将首次阐明Dmrt1在垂体发育中的转录调控作用，并为垂体腺瘤发病机制的研究提供理论依据。

垂体通过分泌激素调节机体的生长发育﹑生殖和代谢，为脊椎动物最重要的内分泌腺。垂体中负责激素产生的是六个内分泌细胞亚群，它们的分化和维持受到许多信号通路和转录因子的严格调控。Dmrt1是保守的性腺发育相关的转录因子，本项目发现dmrt1基因敲除的雄性斑马鱼存在垂体异常膨大且程度日益加重的表型，同时其促性腺激素（GTH）基因的表达显著上调。通过RNA荧光原位杂交发现dmrt1基因敲除的雄性斑马鱼垂体中黄体生成素（LH）和卵泡刺激素（FSH）分泌细胞的数目显著增多，其他几种分泌细胞数目显著降低，说明雄鱼突变体中Dmrt1的缺失引发GTH细胞亚群过度增殖。RNA-Seq和ATAC-Seq联合分析表明，与野生型相比，dmrt1基因敲除的雄性斑马鱼垂体中的差异表达基因在细胞周期相关通路中显著富集，表明细胞周期紊乱是导致dmrt1基因敲除的雄性斑马鱼垂体膨大的原因。