Gene Regulatory Networks for Mullerian Duct Regression

哺乳动物，包括人类，在完全分化成雄性或雌性之前，都会为雄性和雌性生殖道器官发育祖细胞组织。男性生殖道的前体组织称为沃尔菲管，女性生殖道的前体组织称为缪勒管。Wolffian管进一步分化为输精管、附睾管和精囊，而苗勒管分化为输卵管、子宫和上阴道。男性性别分化的一个重要步骤是苗勒管的退化。这种回归始于胎儿睾丸中的抗苗勒氏激素(AMH)转录，大约在胚胎发育的12.5天(E12.5)，并在E17.5天接近完成。众所周知，Müllerian管退行性变需要AMH从胎儿睾丸释放后，与其在Müllerian管间充质中的主要受体AMHR2结合。在实验中，既不表达AMH也不表达Amhr2的雄性基因敲除小鼠没有经历缪勒管退化，这就证明了这一点。因此，AMH/Amhr2对于男性的性别分化是必不可少的。没有功能性AMH或AMHR2的男性患者有子宫，这种情况被称为持续性苗勒管综合征(PMDS)，性发育不同(DSD)。Amhr2表达于Müllerian管间充质细胞、支持细胞、间质细胞和出生后颗粒细胞。已经在体外研究了Amhr2在支持细胞、间质细胞和颗粒细胞中的转录调控。我们描述了苗勒管回归的基因调控网络(GRN)。我们的Müllerian管回归GRN阐明了确定Amhr2的Müllerian管间充质特异性转录增强子的必要性。这项建议使用体内转基因小鼠试验和Müllerian管间充质细胞ATAC-Seq开放染色质评估来确定Amhr2转录所需的顺式元件，以实现Müllerian管退化。这一认识将为Müllerian导管回归的GRN提供信息，并可能为人类DSD的起源提供新的见解。

Mammals, including humans, develop progenitor tissues for both male and female reproductive tract organs before fully differentiating into a male or female. The progenitor tissue for the male reproductive tract is known as the Wolffian duct, and the progenitor tissue for the female reproductive tract is the Müllerian duct. The Wolffian duct further differentiates into the vas deferens, epididymis, and seminal vesicle, while the Müllerian duct differentiates into the oviduct, uterus and upper vagina. An essential step in sex differentiation for males is the regression of the Müllerian ducts. This regression initiates with anti-Müllerian hormone (Amh) transcription in the fetal testes about 12.5 days into embryonic development (E12.5) and approaches completion at E17.5. It is known that Müllerian duct regression requires the binding of AMH, after it is released from the fetal testes, to its primary receptor AMHR2 in the Müllerian duct mesenchyme. This is evidenced by experiments in which male knockout mice that did not express either Amh or Amhr2 did not undergo Müllerian duct regression. Thus, Amh/Amhr2 are essential for male sex differentiation. Male patients without functional AMH or AMHR2 have a uterus, a condition known as Persistent Müllerian Duct Syndrome (PMDS), a difference in sex development (DSD). Amhr2 is expressed in the Müllerian duct mesenchyme, Sertoli, Leydig, and postnatal granulosa cells. Transcriptional regulation of Amhr2 has been studied in Sertoli, Leydig, and granulosa cells in vitro. We have described a gene regulatory network (GRN) for Müllerian duct regression. Our GRN for Müllerian duct regression has illuminated the need to identify the Müllerian duct mesenchyme specific transcriptional enhancer for Amhr2. This proposal uses in vivo transgenic mouse assays and ATAC-seq open chromatin assessments in Müllerian duct mesenchyme cells to identify the cis-elements required for Amhr2 transcription for Müllerian duct regression. This knowledge should inform the GRN for Müllerian duct regression and may provide new insights into the genesis of human DSDs.