Identification and characterization of a nanog homolog in Japanese flounder (Paralichthys olivaceus)
Identification and characterization of a nanog homolog in Japanese flounder (Paralichthys olivaceus)
复制标题
日本牙鲆 (Paralichthys olivaceus) 中 Nanog 同源物的鉴定和表征
DOI：
10.1016/j.gene.2013.08.030
复制
发表时间：
2013-12-01
期刊：
影响因子：
3.5
通讯作者：
Wang, Xubo
中科院分区：
文献类型：
--
作者：
Gao, Jinning;Wang, Jing;Wang, Xubo
含有同源结构域的转录因子nanog在维持哺乳动物胚胎干细胞的多能性和自我更新中起关键作用。干细胞为转基因动物的产生和遗传资源的保存提供了重要而有效的工具。nanog基因在海洋鱼类中的分子遗传结构和表达尚未见报道。本研究从比目鱼中分离并鉴定了nanog基因，为进一步了解鱼类干细胞的多能性机制和开发一种潜在的体内、外干细胞鉴定的分子标记奠定了基础。系统发育、基因结构和染色体同线性分析表明Po-nanog与哺乳动物nanog基因同源。蛋白质序列比较表明，比目鱼Nanog共享低相似性与其他脊椎动物的直系同源物，除了保守的同源结构域。定量RT-PCR分析表明，nanog基因在比目鱼胚胎中呈母系表达，其转录产物从一细胞期到神经胚期均有表达，并在囊胚期达到高峰。整装原位杂交分析表明，转录本存在于早期胚胎的所有卵裂球。组织分布分析表明，nanog仅在性腺中检测到。此外，卵巢中的表达显著高于睾丸。原位杂交结果显示，该基因在卵巢中定位于卵原细胞和卵母细胞的胞质中，在睾丸中仅定位于精原细胞，而在精母细胞和精子细胞中没有定位。启动子区域也被分析为具有几个基本核心启动子元件和转录因子结合位点。所有这些结果表明，Po-Nanog可能在硬骨鱼类和哺乳动物之间具有保守的功能。(C)2013爱思唯尔有限公司版权所有。
The homeodomain-containing transcription factor nanog plays a key role in maintaining the pluripotency and self-renewal of embryonic stem cells in mammals. Stem cells offered as a significant and effective tool for generation of transgenic animals and preservation of genetic resources. The molecular genetic organization and expression of nanog gene in marine fish have not been reported yet In this study, we isolated and characterized the flounder nanog gene as a first step towards understanding the mechanism of the plurpotency of fish stem cells and develop a potential molecular marker to identify the stem cells in vivo and in vitro. Phylogenetic, gene structure and chromosome synteny analysis provided the evidence that Po-nanog is homologous to the mammalian nanog gene. Protein sequence comparison showed that flounder Nanog shared low similarity with other vertebrate orthologs except for a conserved homeodomain. Quantitative RT-PCR analysis showed that flounder nanog was maternally expressed, and the transcripts were present from the one-cell stage to the neurula stage with the peaking at blastula stage. Whole mount in situ hybridization analyses demonstrated that the transcripts were present in all blastomeres of the early embryo. Tissue distribution analysis indicated that nanog was detectable only in gonads. Further, the expression was significantly high in ovary than in testis. In situ hybridization revealed that the transcripts were located in the cytoplasm of the oogonia and oocytes in ovary, only in the spermatogonia but no spermatocytes or spermatids in testis. The promoter region was also analyzed to have several basal core promoter elements and transcription factor binding sites. All these results suggest that Po-Nanog may have a conservative function between teleosts and mammals. (C) 2013 Elsevier B.V. All rights reserved.