Takase M, Nakajima T, Nakamura M
Molecular Medicine Unit, Department of Molecular Pathology, University College London, UK.
Biochim Biophys Acta. 2000 Nov 15;1494(1-2):195-200. doi: 10.1016/s0167-4781(00)00201-3.
Fushi tarazu transcription factor-1 (FTZ-F1), a member of the nuclear hormone receptor superfamily, is a regulator for fushi tarazu gene expression in Drosophila. Its expression pattern during organogenesis in vertebrates, however, is not known yet. In this study, we cloned a frog FTZ-F1 homologue (rrFTZ-F1alpha) and analyzed its expression and localization during gonadal development of the frog Rana rugosa. Cloned rrFTZ-F1alpha cDNA encoded a protein of 501 amino acids including the regions I-III and FTZ-F1 box that are evolutionally conserved in the FTZ-F1 superfamily. rrFTZ-F1alpha shared high similarity at the amino acid level with mouse LRH-1 (76%), human FTF (92%), chicken OR2.0 (92%), Xenopus laevis FF1rA (94%) and zebrafish FF1A (82%). Northern blot analysis showed that the rrFTZ-F1alpha mRNA at a size of 7.4 kb was the most prominent in the testis among various tissues of adult frogs examined. The RT-PCR analysis revealed that the expression of rrFTZ-F1alpha was weak in the gonad of tadpoles before stage XVI, but it became stronger in the testis of froglets at stage XXV and much higher in the testis of frogs 2 months after metamorphosis. In addition, in situ hybridization analysis revealed that the rrFTZ-F1alpha gene was transcribed in germ cells except for sperm in the testis, and in oocytes at stage A in the ovary of frogs 2 months after metamorphosis. Together, these results suggest that FTZ-F1alpha probably plays an important role in differentiation of germ cells in the gonad of frogs in both sexes.
腹节基因缺失转录因子-1（FTZ-F1）是核激素受体超家族的成员之一，是果蝇中腹节基因表达的调节因子。然而，其在脊椎动物器官发生过程中的表达模式尚不清楚。在本研究中，我们克隆了青蛙FTZ-F1的同源物（rrFTZ-F1α），并分析了其在皱皮蛙性腺发育过程中的表达和定位。克隆的rrFTZ-F1α cDNA编码一个由501个氨基酸组成的蛋白质，包括在FTZ-F1超家族中进化保守的I-III区和FTZ-F1框。rrFTZ-F1α在氨基酸水平上与小鼠LRH-1（76%）、人类FTF（92%）、鸡OR2.0（92%）、非洲爪蟾FF1rA（94%）和斑马鱼FF1A（82%）具有高度相似性。Northern印迹分析表明，在成年青蛙的各种组织中，7.4 kb大小的rrFTZ-F1α mRNA在睾丸中最为显著。RT-PCR分析显示，rrFTZ-F1α在第十六阶段之前的蝌蚪性腺中表达较弱，但在第二十五阶段的幼蛙睾丸中表达增强，在变态后2个月的青蛙睾丸中表达更高。此外，原位杂交分析表明，rrFTZ-F1α基因在变态后2个月的青蛙睾丸中除精子外的生殖细胞以及卵巢A期的卵母细胞中都有转录。总之，这些结果表明FTZ-F1α可能在青蛙两性性腺中生殖细胞的分化中起重要作用。
