Department of Molecular and Cellular Biology, University of California Davis, One Shields Avenue, Davis, CA 95616, USA.
Dev Biol. 2013 Apr 1;376(1):43-50. doi: 10.1016/j.ydbio.2013.01.016. Epub 2013 Jan 21.
Sex in zebrafish is not determined by a major chromosomal locus, but instead relies on a mechanism that is influenced by a germ cell-derived signal, as animals that lack germ cells, or specifically oocytes, develop as phenotypic males. These data suggest that during primary sex determination, an oocyte-derived signal acts on the bipotential somatic gonad to promote the female-specific program. However, it is not known if germ cells are required only during the primary sex-determining window, or if they are required throughout adult life to maintain the female sexual phenotype. Here, we show that while wild-type zebrafish do not switch sex as adults, germ cell-depleted adult females readily convert to a male phenotype. Notably, when oocytes are depleted, but germline stem cells remain, adult females sex-revert to sperm-producing males, indicating that a germ cell-derived signal acts on the somatic gonad to promote female development directly or indirectly by repressing male-specific gene expression. These results also confirm that signals from the somatic gonad in turn ensure that the sex appropriate gamete is produced.
鱼类的性别并非由主要的染色体决定，而是依赖于一种由生殖细胞衍生的信号机制，因为缺乏生殖细胞，特别是卵母细胞的动物会发育成表型雄性。这些数据表明，在初级性别决定过程中，卵母细胞衍生的信号作用于双潜能体生殖腺，以促进雌性特异性程序。然而，目前尚不清楚生殖细胞是否仅在初级性别决定窗口期间需要，或者它们是否在整个成年期都需要维持雌性性表型。在这里，我们表明，虽然野生型斑马鱼在成年后不会改变性别，但生殖细胞耗竭的成年雌性很容易转变为雄性表型。值得注意的是，当卵母细胞耗尽，但生殖干细胞仍然存在时，成年雌性会恢复到产生精子的雄性，这表明生殖细胞衍生的信号直接或间接地作用于体生殖腺，通过抑制雄性特异性基因表达来促进雌性发育。这些结果也证实，来自体生殖腺的信号反过来又确保了产生适当的配子。
