Germ cells are essential for sexual dimorphism in the medaka gonad
Germ cells are essential for sexual dimorphism in the medaka gonad
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DOI：
10.1073/pnas.0609932104
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发表时间：
2007-10-23
影响因子：
11.1
通讯作者：
Tanaka, Minoru
中科院分区：
文献类型：
--
作者：
Kurokawa, Hiromi;Saito, Daisuke;Tanaka, Minoru
为了进一步阐明生殖细胞在性腺性别分化中的作用，我们使用了青鳉，一种硬骨鱼，通过吗啉介导的cxcr4基因敲除产生从性腺发生开始就缺乏生殖细胞的突变体。由此产生的生殖细胞缺陷青鳉表现出第二性征的雌性到雄性的性逆转，伴随着雄激素水平的增加和雌激素水平的降低。不能维持颗粒细胞或雌激素产生细胞也发生在cxcr4型变体性别分化的早期阶段，在性腺形态发生开始之前。相反，雄性激素产生细胞在生殖细胞缺陷青鳉中不受影响。此外，在这些突变体中形成了一个表达雄性特异性基因的单一管状性腺，而与遗传性别无关。值得注意的是，这些突变表型中的每一个都以体细胞自主的方式发生，这表明性腺体细胞在没有生殖细胞的情况下倾向于男性发育。这凸显了生殖细胞在性腺性二型性中的重要性。
To further elucidate the roles of germ cells in the sex differentiation of gonads, we have used the medaka, a teleost fish, to generate mutants that lack germ cells from the onset of gonadogenesis by the morpholino-mediated knockdown of cxcr4. The resulting germ-cell-deficient medaka show female-to-male sex reversal of their secondary sex characteristics, accompanied by increased levels of androgen and reduced levels of estrogen. A failure to maintain granulosa cells or estrogen-producing cells also occurs at early stages of sex differentiation in the cxcr4 morphants, before the initiation of gonadal morphogenesis. In contrast, androgen-producing cells are unaffected in germ-cell-deficient medaka of either sex. In addition, a single tube-like gonad that expresses male-specific genes is formed in these mutants irrespective of the genetic sex. Significantly, each of these mutant phenotypes occurs in a somatic cell-autonomous manner, suggesting that gonadal somatic cells are predisposed toward male development in the absence of germ cells. This highlights the importance of germ cells in the sexual dimorphism of the gonads.