脊椎动物活化的(蛋白)激酶C受体1(receptor for activated C-kinase1,RACK1)在胚胎发育过程中起着至关重要的作用.克隆了RACK1基因在青岛文昌鱼(Branchiostoma belcheri)中的同源基因AmphiRACK1,对其进行了系统的进化学分析,并研究了该基因在正常胚胎发育过程中和经LiCl处理胚胎发育中的时空表达图式.系统进化学分析结果表明,文昌鱼RACK1位于脊椎动物进化枝的基部.在正常胚胎发育中,AmphiRACK1基因在脑泡、神经管和体节中都有明显的表达.在经LiCl处理的胚胎中,该基因在体节中的分节型表达变模糊,表达下调;在脑泡和神经管中的表达下调甚至消失.此外,在成体文昌鱼的轮器、鳃血管、肝盲囊和肠上皮以及精巢中都检测到AmphiRACK1基因不同程度的表达.
Smad family proteins are identified as intracellular signal mediators of the TGF-β superfamily.In this study,we identified two novel members of the Smad family,termed as AmphiSmad1/5/8 and AmphiSmad4,from Chinese amphioxus.Both AmphiSmad1/5/8 and AmphiSmad4 showed a typical domain structure of Smad proteins consisting of conserved MH1 and MH2 domains.Phylogenetic analysis placed AmphiSmad1/5/8 in the Smad1,5 and 8 subgroup of the R-Smad subfamily,and AmphiSmad4 in the Co-Smad subfamily.The spatial and temporal gene expression patterns of AmphiSmad1/5/8 and AmphiSmad4 showed that they may be involved in the embryonic development of notochord,myotome and alimentary canal,and may help to establish the specification of dorsal-ventral axis of amphioxus.Moreover,AmphiSmad1/5/8 and AmphiSmad4 showed extensive distribution in all adult tissues examined,suggesting that these two genes may play important roles in the morphogenesis of a variety of tissues especially notochord and gonad.
