最新一期《实验动物学杂志·生态遗传学和生理学》(4月号)在封面文章位置发表了中科院水生所关于“石斑鱼性反转和配子发生期间Sox3基因差异表达和动态变化”论文。这篇论文是该所桂建芳研究员指导的博士研究生姚波和副研究员周莉等共同完成的，封面图片显示了SOX3在原始生殖细胞和初级卵母细胞中清晰的荧光定位图像。
石斑鱼是我国南方沿海地区网箱养殖的重要经济鱼类之一。其在生活史中具有由雌变雄的性反转过程，因此雄性亲鱼短缺是限制产业发展的主要因素之一，同时它也是研究鱼类生殖调控和性别分化分子机制的一个独特对象。在国家“973”和“863”等计划项目的支持下，从“十五”开始，水生所鱼类发育遗传学和细胞工程学科组以南方沿海普遍养殖的斜带石斑鱼(E. Coioides)为研究对象，围绕生殖内分泌调控轴，构建了石斑鱼下丘脑、垂体和性腺的一系列cDNA文库，筛选和克隆到了一批参与生殖调控和性腺分化的重要功能基因，分析了一批基因随着性反转进程在垂体、性腺中或在胚胎发育过程中的时空表达图谱。刚刚在《实验动物学杂志·生态遗传学和生理学》上发表的是这一系列研究的论文之一。
该文详细报道了石斑鱼性反转和配子发生期间SOX3蛋白在不同发育阶段生殖细胞中的定位及其动态变化。在雌性性腺中，SOX3蛋白存在于分化中的原始生殖细胞、卵原细胞和不同发育阶段的卵母细胞核中，而在雄性性腺中则存在于分化中的原始生殖细胞和支持细胞中。当SOX3持续表达时，SOX3阳性的原始生殖细胞朝卵原细胞和卵母细胞方向发育；当Sox3表达停止时，原始生殖细胞则进入精子发生过程。该文重要的创新点之一是巧妙地利用雌雄同体的石斑鱼同时具有不同发育阶段的雌性配子细胞和雄性配子细胞的特性，通过一系列的免疫荧光定位观察，揭示Sox3的表达是原始生殖细胞进入配子发生的一个时间检验点，其表达是否持续，将决定配子发生向两种截然不同的方向进行。因而这一发现证实了SOX3在卵子发生和配子细胞分化中的潜在调控作用，并确信SOX3在卵子发生中的作用比在精子发生中的作用要大得多。
部分英文原文:
Research Article
Differential expression and dynamic changes of SOX3 during gametogenesis and sex reversal in protogynous hermaphroditic fish
Bo Yao, Li Zhou, Yang Wang, Wei Xia, Jian-Fang Gui *
State Key Laboratory of Freshwater Ecology and Biotechnology, Wuhan Center for Developmental Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Wuhan, China
email: Jian-Fang Gui (jfgui@ihb.ac.cn)
*Correspondence to Jian-Fang Gui, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
Bo Yao and Li Zhou have contributed equally to this work.
Bo Yao and Li Zhou have contributed equally to this work.
Funded by:
The National Basic Research Program of China; Grant Number: 2004CB117401
The Innovation group project of Hubei Province; Grant Number: 2004ABC005
[NextPage]
Abstract
SOX3 has been suggested to play significant roles in gametogenesis and gonad differentiation of vertebrates, but the exact cellular localization evidence is insufficient and controversial. In this study, a protogynous hermaphrodite fish Epinephelus coioides is selected to analyze EcSox3 differential expression and the expression pattern in both processes of oogenesis and spermatogenesis by utilizing the advantages that gonad development undergoes transition from ovary to intersexual gonad and then to testis, and primordial germ cells and different stage cells during oogenesis and spermatogenesis are synchronously observed in the transitional gonads. The detailed and clear immunofluoresence localization indicates that significantly differential expression and dynamic changes of Sox3 occur in the progresses of gametogenesis and sex reversal, and EcSOX3 protein exists in the differentiating primordial germ cells, oogonia, and different stage oocytes of ovaries, and also in the differentiating primordial germ cells and the Sertoli cells of testis. One important finding is that the EcSox3 expression is a significant time point for enterable gametogenesis of primordial germ cells because EcSOX3 is obviously expressed and localized in primordial germ cells. As EcSox3 continues to express, the EcSOX3-positive primordial germ cells develop toward oogonia and then oocytes, whereas when EcSox3 expression is ceased, the EcSOX3-positive primordial germ cells develop toward spermatogonia. Therefore, the current finding of EcSOX3 in the differentiating primordial germ cells again confirms the potential regulatory role in oogenesis and germ cell differentiation. The data further suggest that SOX3, as a transcription factor, might have more important roles in oogenesis than in spermatogenesis. J. Exp. Zool. 307A:207-219, 2007. © 2007 Wiley-Liss, Inc.
