Doublesex基因在对虾性别决定和分化中的功能研究

Due to the growth trait of penaeid shrimp displays an obvious sex dimorphism, sex control studies have an important value in shrimp breeding. However, the molecular mechanism regulating shrimp sex determination and differentiation is still not clear now, which severely blocks the development of sex control technologies. In previous studies, we obtained the homologues of sex lethal, transformer 2 and doublesex genes, members of Drosophila sex determination pathway, from the Chinese shrimp. The expression level of them are obviously different in both sexes. Based on these data, we presume that the sex determination mechanism of shrimp is similar with that of Drosophila. In addition, as the key transcriptional factor in sex determination pathway, we found the binding site of doublesex in the 5'-flanking sequence of the shrimp sex differentiation regulating gene, the insulin-like androgenic gland hormone gene. In order to further investigate the molecular mechanism of shrimp sex determination, the present project will focus on the gene function studies of shrimp doublesex gene based on the previous studies. Through studying the effect of doublesex gene on gonad development and on the transcription of the insulin-like androgenic gland hormone gene and identifying the downstream genes regulated by doubelsex gene, we will illustrate the function of doublesex gene in the process of sex determination and differentiation in shrimp. The data will not only provide theory evidence to elucidate the molecular mechanism of sex determination and differentiation in shrimp and even in crustacean, but also provide directions on developing sex control biotechnologies for achieving monosex culture.

对虾生长性状存在明显的性别二态性，因而性别控制研究在对虾育种中具有重要意义。然而，由于对对虾性别决定和分化机制了解较少，严重制约了性别控制技术的研发。在前期研究中我们发现中国对虾中存在果蝇性别决定基因sex lethal、transformer 2和doublesex（dsx）的同源基因，其表达存在明显的性别差异，由此推测对虾可能具有与果蝇类似的性别决定机制。Dsx作为性别决定的关键转录因子，我们发现控制对虾性别分化的促雄性腺素基因5'侧翼序列含有其潜在结合位点。为深入探讨对虾性别决定的机制，本项目拟在前期工作的基础上，对对虾dsx基因的功能开展研究，通过分析其对性腺发育和促雄性腺素基因表达的影响，并鉴定dsx调控的下游基因，明确该基因在对虾性别决定和分化中的功能。研究结果不仅可为阐明对虾乃至甲壳动物性别决定和分化的分子机制提供重要依据，也为开发对虾性别控制技术用于单性化养殖提供重要指导。

对虾生长性状存在明显的性别二态性，因而性别控制研究在对虾育种中具有重要意义。然而，由于对对虾性别决定和分化机制了解较少，严重制约了性别控制技术的研发。本项目首先筛选获得了两个用于鉴定对虾遗传性别的DNA分子探针，可以简单区别中国对虾的遗传性别，在对虾性别决定、性别分化及性别控制的研究中具有重要的应用价值；然后以FcDsx基因为核心，克隆了该基因的全长序列，分析了基因结构特征，并利用RNAi技术研究了该基因对促雄性腺素基因IAG基因及性腺发育的影响，获取了FcDsx基因的表达特征及对促性腺素基因IAG的表达调控作用，初步揭示了FcDsx基因在对虾性别分化过程中的作用，对阐释对虾乃至甲壳动物的性别决定和性别分化的分子机制奠定了基础；同时，首次鉴定获得了下游基因IAG的受体基因IR，研究了IR基因的表达模式及其与IAG的相互作用关系，初步确定了IR为IAG的受体基因，不但对于阐释对虾性别分化的分子调控机制提供重要证据，也将为针对IR开发用于性别控制的化合物提供研究基础；另外，研究了眼柄中的上游调控激素CHH在对虾性别分化中的作用，为揭示对虾眼柄神经肽调控性别分化过程提供重要证据。本项目的研究，不但为进一步阐释甲壳动物性别决定和分化的分子调控网络提供了重要数据，而且为开发新的性别控制技术提供了支撑。