中文摘要：

Hox基因是脊椎动物一类重要的生长和发育调节基因，其所编码具螺旋-转角-螺旋结构的转录因子能与靶基因特定区域DNA结合，从而调节动物胚胎发育过程中体轴的形成和器官组织的生长。本研究采用cDNA末端快速扩增法（RACE）克隆了团头鲂HoxB3a的全长cDNA，并对团头鲂不同时期的胚胎和成鱼的不同组织进行了RT—PCR分析，以探索HoxB3a基因的时空表达特征。序列比对分析结果显示，团头鲂HoxB3a编码的氨基酸序列与斑马鱼（Danio rerio）、大西洋鲑（Salmo salar）、红鳍东方纯（Takifugu rubripes）、青锵（Oryzias latipes）、条纹鲈（Morone saxatilis）、人（Homo sapiens）和小鼠（Mus musculus）的相似性分别为96％、85％、77％、76％、78％、66％和67％，同源性较高，这说明HoxB3a基因在长期的进化中具有较高保守性。RT—PCR结果表明，团头鲂HoxB3a基因从16hpf（hours post fertilization）胚胎期到出苗期都有表达，在成鱼大部分器官或组织中具表达活性，预示该基因存在着重要的生物学功能。Hoxb3a基因全长cDNA的克隆、胚胎不同阶段表达及组织细胞表达特征研究，为进一步探索该基因的发育通路奠定了基础。

英文摘要：

The Hox genes are a family of important growth and development regulatory genes in vertebrate. Their encoding helix-turn-helix transcription factors can combine with DNA in specific region to regulate the axial pattern formation and the growth of organs and tissues during ontogeny. In this study, the complete cDNAs of Megalobrama amblycephala Hoxb3a gene was cloned by rapid amplification of eDNA ends （RACE） and gene expression in embryos at different stages and in different tissues of adult fish were studied by RT- PCR. The deduced amino acid sequence was aligned with Danio rerio, Salmo salar, Takifugu rubripes, Oryzins latipes, Morone saxatilis, Homo sapiens and Mus musculus, and the sequence similarities are 96% , 85% ,77%, 76%, 78%, 66% and 67%, respectively, which illustrated that the HoxB3a gene was very conservative in the progress of evolution. The results of RT-PCR showed that Hoxb3a gene expressed from 16 hpf （hours post fertilization） to larvae and was almost found in all studied.