Guo Yiqing, Cheng Hanhua, Huang Xiao, Gao Shang, Yu Hongshi, Zhou Rongjia
Department of Genetics and Center for Developmental Biology, College of Life Sciences, Wuhan University, Wuhan 430072, PR China.
Biochem Biophys Res Commun. 2005 May 13;330(3):950-7. doi: 10.1016/j.bbrc.2005.03.066.
Many basic cellular processes are shared across vast phylogenetic distances, whereas sex-determining mechanisms are highly variable between phyla although the existence of two sexes is nearly universal in the animal kingdom. The only molecular similarity in sex determination found so far between phyla is among the fly doublesex, worm mab-3, and vertebrate Dmrt1/DMY, which contain a zinc-finger-like DNA-binding motif, DM domain. Here we report that three isoforms of the zebrafish Dmrt1 were generated in gonads by multiple alternative splicing, which encoded predicted proteins with 267, 246, and 132 amino acids, respectively. By cDNA cloning and genomic structure analysis, we found that there were seven exons of Dmrt1, which were alternatively spliced to generate the Dmrt1 isoforms. Northern blotting analysis revealed that expression of zebrafish Dmrt1 was higher in testis than ovary. Real time fluorescent quantitative RT-PCR indicated that expression of isoform a of Dmrt1 was dominantly higher than those of Dmrt1 b and c. Furthermore, in situ hybridization to gonads sections showed that Dmrt1 was expressed in developing germ cells of both testis and ovary, suggesting that the Dmrt1 gene is not only associated with testis development, but also, may be important in ovary differentiation of zebrafish.
许多基本的细胞过程在漫长的系统发育距离中是共有的，而性别决定机制在不同门类之间高度可变，尽管两性的存在在动物界几乎是普遍的。到目前为止，在不同门类之间发现的性别决定中唯一的分子相似性存在于果蝇的双性基因、线虫的mab - 3以及脊椎动物的Dmrt1/DMY之间，它们都含有一个类似锌指的DNA结合基序，即DM结构域。在此我们报告，斑马鱼Dmrt1的三种异构体是通过多种可变剪接在性腺中产生的，分别编码预测的含267、246和132个氨基酸的蛋白质。通过cDNA克隆和基因组结构分析，我们发现Dmrt1有七个外显子，它们通过可变剪接产生Dmrt1异构体。Northern印迹分析显示，斑马鱼Dmrt1在睾丸中的表达高于卵巢。实时荧光定量RT - PCR表明，Dmrt1异构体a的表达明显高于Dmrt1 b和c。此外，对性腺切片的原位杂交显示，Dmrt1在睾丸和卵巢的发育中的生殖细胞中都有表达，这表明Dmrt1基因不仅与睾丸发育有关，而且可能在斑马鱼卵巢分化中也很重要。
