Sichuan Provincial Key-Laboratory of Protection and Utilization of Animal Genetic Resources in Qinghai-Tibet Plateau, Southwest University for Nationalities, Chengdu 610041, PR China.
Gen Comp Endocrinol. 2013 Jun 15;187:1-5. doi: 10.1016/j.ygcen.2013.03.023. Epub 2013 Apr 8.
Growth hormone (GH), insulin-like growth factor-I (IGF-I), and II (IGF-II) play a key role in the development of preantral to preovulatory follicles in some species. To better understand the role of these genes in controlling follicular development and fecundity in goats, in the present study, we first cloned the cDNA encoding GH, IGF-I and IGF-II from prolific Lezhi black goat and non-prolific Tibetan goat (Capra hircus), and their mRNA expression between the two breeds were compared. By reverse transcriptase-polymerase chain reaction (RT-PCR) strategy, we obtained full-length 688-bp GH, 493-bp IGF-I, and 566-bp IGF-II cDNAs, encoding for 217 amino acid (aa) GH, 154 aa IGF-I, and 179 aa IGF-II putative proteins. Analysis of their nucleotide and amino acid sequences revealed a high degree of identity between the two breeds, although one base change in GH resulted in one amino acid substitution in the translated proteins. However, two base changes in IGF-I and IGF-II did not lead to any amino acid changes. Real-time PCR analyses revealed that in the middle of estrus, GH, IGF-I and IGF-II genes were expressed, albeit at different levels, in all three tissues (anterior pituitary, endometrium and ovary) examined. GH was most highly expressed in ovary (P<0.01) and its expression was greater in all three tissues examined in Lezhi black goat than in Tibetan goat (P<0.05). IGF-I and IGF-II genes were expressed at a higher (P<0.05) level in anterior pituitary of Lezhi black goat than that in Tibetan goat, but they had a similar expression pattern in endometrium and ovary. These results provide the foundation of information required for future studies of these gene effects on goat fecundity.
生长激素（GH）、胰岛素样生长因子-I（IGF-I）和 II（IGF-II）在某些物种的原始卵泡发育到排卵前卵泡中起着关键作用。为了更好地了解这些基因在控制山羊卵泡发育和繁殖力中的作用，本研究首先从高产乐至黑山羊和非高产西藏山羊（Capra hircus）中克隆了 GH、IGF-I 和 IGF-II 的 cDNA，并比较了它们在两个品种中的 mRNA 表达。通过逆转录聚合酶链反应（RT-PCR）策略，我们获得了全长 688bp 的 GH、493bp 的 IGF-I 和 566bp 的 IGF-II cDNA，分别编码 217 个氨基酸（aa）的 GH、154 个 aa 的 IGF-I 和 179 个 aa 的 IGF-II 假定蛋白。对它们的核苷酸和氨基酸序列进行分析表明，尽管 GH 中的一个碱基变化导致翻译蛋白中的一个氨基酸取代，但两个品种之间存在高度的同源性。然而，IGF-I 和 IGF-II 中的两个碱基变化并没有导致任何氨基酸变化。实时 PCR 分析显示，在发情中期，GH、IGF-I 和 IGF-II 基因在所有三个组织（垂体前叶、子宫内膜和卵巢）中均有表达，尽管表达水平不同。GH 在卵巢中的表达最高（P<0.01），并且在乐至黑山羊的所有三个组织中的表达均高于西藏山羊（P<0.05）。IGF-I 和 IGF-II 基因在前垂体中的表达水平在乐至黑山羊中较高（P<0.05），但在子宫内膜和卵巢中的表达模式相似。这些结果为进一步研究这些基因对山羊繁殖力的影响提供了所需的信息基础。
