United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Tokyo, Japan.
Chromosome Res. 2012 Jan;20(1):163-76. doi: 10.1007/s10577-011-9264-x.
DMRT1, which is found in many vertebrates, exhibits testis-specific expression during the sexual differentiation period, suggesting a conserved function of DMRT1 in the testicular development of vertebrate gonads. However, functional analyses have been reported only in mammals. The current study focused on the Dmrt1 function in the teleost medaka, Oryzias latipes, which has an XX-XY sex determination system. Although medaka sex is determined by the presence or absence of the Y chromosome-specific gene Dmy, we demonstrated that in one Dmrt1 mutant line, which was found by screening a gene-driven mutagenesis library, XY mutants developed into normal females and laid eggs. Histological analyses of this mutant revealed that the XY mutant gonads first developed into the normal testis type. However, the gonads transdifferentiated into the ovary type. The mutant phenotype could be rescued by transgenesis of the Dmrt1 genomic region. These results show that Dmrt1 is essential to maintain testis differentiation after Dmy-triggered male differentiation pathway.
DMRT1 存在于许多脊椎动物中，在性分化期表现出睾丸特异性表达，这表明 DMRT1 在脊椎动物性腺的睾丸发育中具有保守功能。然而，功能分析仅在哺乳动物中报道过。本研究集中在性染色体决定的硬骨鱼斑马鱼（Oryzias latipes）的 Dmrt1 功能上，斑马鱼的性别由存在或不存在 Y 染色体特异性基因 Dmy 决定。尽管如此，我们发现通过筛选基因驱动的诱变文库，在一个 Dmrt1 突变体系中，XY 突变体发育成正常的雌性并产卵。对这种突变体的组织学分析表明，XY 突变体的性腺首先发育成正常的睾丸类型。然而，性腺会转变成卵巢类型。Dmrt1 基因组区域的转基因可以挽救突变表型。这些结果表明，在 Dmy 触发的雄性分化途径后，Dmrt1 对于维持睾丸分化是必需的。
