Wang De-Shou, Jiao Baowei, Hu Chongjiang, Huang Xigui, Liu Zhihao, Cheng Christopher H K
Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, Chongqing 400715, China.
Biochem Biophys Res Commun. 2008 Mar 7;367(2):336-41. doi: 10.1016/j.bbrc.2007.12.136. Epub 2007 Dec 31.
Distinct from the conventional IGFs (IGF-1 and IGF-2), here we report the identification of a novel IGF (herein called IGF-3) encoded by a separate gene from teleost species. The IGF-3 cDNA sequences were cloned from tilapia and zebrafish, and predicted from the medaka genome and EST databases. Similar to IGF-1 and IGF-2, IGF-3 is also comprised of five domains (B, C, A, D, E) with a similar tertiary protein structure, despite a low sequence homology among them. Phylogenetic analysis reveals that the IGF-3 sequences from different teleosts cluster to form a distinctive clade separate from IGF-1 and IGF-2. The expression of this novel IGF-3 is gonad-specific and starts early in fish development. In situ hybridization revealed that IGF-3 is expressed in the somatic cells and later in granulosa cells of the ovary, and in the interstitial cells of the testis. These findings highlight the importance of this novel IGF in teleost gonadal development and reproduction.
与传统的胰岛素样生长因子（IGF-1和IGF-2）不同，我们在此报告了一种新的胰岛素样生长因子（在此称为IGF-3）的鉴定，它由硬骨鱼物种的一个单独基因编码。IGF-3 cDNA序列从罗非鱼和斑马鱼中克隆得到，并从青鳉基因组和EST数据库中预测得到。与IGF-1和IGF-2相似，IGF-3也由五个结构域（B、C、A、D、E）组成，具有相似的三级蛋白质结构，尽管它们之间的序列同源性较低。系统发育分析表明，来自不同硬骨鱼的IGF-3序列聚在一起，形成一个与IGF-1和IGF-2不同的独特分支。这种新的IGF-3的表达具有性腺特异性，在鱼类发育早期就开始了。原位杂交显示，IGF-3在卵巢的体细胞中表达，随后在颗粒细胞中表达，在睾丸的间质细胞中也有表达。这些发现突出了这种新的IGF在硬骨鱼性腺发育和繁殖中的重要性。
