Department of Animal Science, Graduate School of Agricultural Science, Kobe University, Kobe, Hyogo 657-8501, Japan.
Poult Sci. 2014 Apr;93(4):953-8. doi: 10.3382/ps.2013-03672.
Sex of birds is genetically determined by the inheritance of sex chromosomes (ZZ for male and ZW for female), and the Z-linked gene named doublesex and mab-3 related transcription factor 1 (DMRT1) is a candidate sex-determining gene in avian species. However, the mechanisms underlying sex determination in birds are not yet understood, and the expression patterns of the DMRT1 protein in urogenital tissues have not been identified. In the current study, we used immunohistochemistry to investigate the detailed expression patterns of the DMRT1 protein in the urogenital systems (including Müllerian ducts) in male and female chicken embryos throughout embryonic development. Gonadal somatic cells in the male indifferent gonads showed stronger expressions of DMRT1 compared with those in the female indifferent gonads well before the presumptive period of the sex determination, and Sertoli cells forming testicular cords expressed DMRT1 in the testes after sex determination. Germ cells expressed DMRT1 equally in males and females after sex determination. The expression was continuous in males, but in females it gradually disappeared from the germ cells in the central part of the cortex of the left ovary toward both edges. The DMRT1 was also detected in the tubal ridge, which is a precursor of the Müllerian duct, and at the mesenchyme and outermost coelomic epithelium of the Müllerian duct in both sexes. Strong expression was observed in the males, but it was restricted to coelomic epithelium after the regression of the duct started. Thus, we observed the detailed spatiotemporal expression patterns of DMRT1 in the developing chicken urogenital systems throughout embryonic development, suggesting its various roles in the development of urogenital tissues in the chicken embryo.
鸟类的性别由性染色体的遗传决定（ZZ 为雄性，ZW 为雌性），而与 Z 连锁的性别决定基因双性和 mab-3 相关转录因子 1（DMRT1）是鸟类种间候选性别决定基因。然而，鸟类性别决定的机制尚不清楚，DMRT1 蛋白在泌尿生殖组织中的表达模式也尚未确定。在本研究中，我们使用免疫组织化学技术研究了 DMRT1 蛋白在雄性和雌性鸡胚泌尿生殖系统（包括 Müllerian 管）中的详细表达模式。在性别决定的假定时期之前，雄性未分化性腺中的体生殖细胞比雌性未分化性腺中的体生殖细胞表现出更强的 DMRT1 表达，形成睾丸索的支持细胞在性别决定后在睾丸中表达 DMRT1。性别决定后，生殖细胞在雄性和雌性中均表达 DMRT1。在雄性中表达是连续的，但在雌性中，它逐渐从左侧卵巢皮质中央的生殖细胞中消失，向卵巢皮质的两侧边缘消失。DMRT1 也在输卵管嵴中检测到，输卵管嵴是 Müllerian 管的前体，在两性的 Müllerian 管的间质和最外层体腔上皮中也检测到 DMRT1。在雄性中观察到强烈的表达，但在开始退化时仅限于体腔上皮。因此，我们观察了 DMRT1 在鸡泌尿生殖系统发育过程中的详细时空表达模式，表明其在鸡胚泌尿生殖组织发育中的多种作用。
