Hu Qiaomu, Xiao Hanbing, Wang Qilong, Tian Haifeng, Meng Yan
Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, Hubei, 430223, China.
Tengzhou Fisheries Center, Tengzhou, Shandong, 277500, China.
Reprod Fertil Dev. 2018 Mar;30(4):634-642. doi: 10.1071/RD17049.
In the present study, 21 forkhead box (Fox) genes were identified in Andrias davidianus, including 13 full-length genes and eight partial sequences. Phylogenetic analysis showed that most were conserved in other investigated amphibians, whereas the Foxk1 gene was found exclusively in A. davidianus. Molecular evolution analysis indicated that most Fox genes underwent purifying selection, whereas two sites of the adFoxp4 gene showed positive selection and were located on the adFoxp4 protein surface. Expression profiles of all Fox genes identified were analysed in the hypothalamic-pituitary-gonad axis by reverse transcription-quantitative polymerase chain reaction. Eighteen genes exhibited sexually dimorphic expression (15 ovary-biased and three testis-biased genes), whereas two genes showed no difference between ovary and testis. Further investigation of 12 selected sexually dimorphic Fox genes showed changes in the expression profile of 11 genes in the ovary of larvae reared at high temperatures (28°C). The results of the present study provide information on Fox genes in an amphibian and suggest that they play key roles in sexual development and reproduction in A. davidianus.
在本研究中，在大鲵中鉴定出21个叉头框（Fox）基因，包括13个全长基因和8个部分序列。系统发育分析表明，大多数基因在其他被研究的两栖动物中是保守的，而Foxk1基因仅在大鲵中发现。分子进化分析表明，大多数Fox基因经历了纯化选择，而adFoxp4基因的两个位点显示出正选择，且位于adFoxp4蛋白表面。通过逆转录-定量聚合酶链反应分析了在所有已鉴定的Fox基因在下丘脑-垂体-性腺轴中的表达谱。18个基因表现出性别二态性表达（15个卵巢偏向性基因和3个睾丸偏向性基因），而两个基因在卵巢和睾丸之间没有差异。对12个选定的性别二态性Fox基因的进一步研究表明，在高温（28°C）饲养的幼虫卵巢中，11个基因的表达谱发生了变化。本研究结果提供了有关两栖动物中Fox基因的信息，并表明它们在大鲵的性别发育和繁殖中起关键作用。
