寒冷环境下鱼类抗寒抗冻的细胞内在机制探讨

Discussion on the intracellular mechanism of cold and freezing resistance of fish in cold environment

研究黑鲷抗冻关键基因家族,以进一步了解鱼类相关基因的结构及功能,为后续研究PI3K/AKT信号通路及关键基因奠定基础。基于已有的基因家族成员,从黑鲷的基因组中筛选了AKT、CK的基因家族成员,对其分子质量、等电点、motif结构、保守结构域等进行分析,并与近缘物种构建系统进化树。结果表明,鱼类的AKT基因家族蛋白保守性较高,AKT序列单独聚为一支,其中AKT1、AKT3和同为鲷科的金头鲷亲缘关系最近,二者又共同和同为鲈形目的大黄鱼聚为一支;AKT2虽然和鱼类聚为一支,但和其他鱼类的亲缘关系均较远。在黑鲷中鉴定出肌型肌酸激酶(mck)和脑型肌酸激酶(bck)2种同功酶,二者长度和分子量基本一致,且都包含creatine kinase结构域,其中哺乳动物的mck和bck均与鱼类的bck亲缘关系较近,但和鱼类相比又自成一支。在mck中,黑鲷与金头鲷具有较紧密的亲缘关系,而bck中,黑鲷与大黄鱼亲缘关系最近,相比于其他鱼类,又单独聚为另一支。

In order to further understand the structure and function of fish-related genes and lay the foundation for the follow-up study of PI3K/AKT signaling pathway and key genes,we studied the key genes family of black seabream antifreeze. Based on the existing gene family members,AKT and CK gene family members were screened from the genome of Sparus macrocephalus. Their molecular weight,isoelectric point,motif structure and conserved domain were analyzed,and the phylogenetic tree was constructed with related species. The results showed that the AKT gene family proteins of fish were highly conserved,and the AKT sequence was clustered into a single branch. Among them,AKT1 and AKT3 were closely related to those of glithead seabream,and they were clustered into a branch with Pseudosciaena crocea. AKT2 is clustered with fish,but had a distant genetic relationship with other fish. Muscle creatine kinase(mck)and brain creatine kinase(bck)were identified in black seabream. The length and molecular weight of mck and bck were basically the same,and both of them contained creatine kinase domain. The mck and bck of mammals were closely related to the bck of fish. However,compared with fish,it formed a branch. In mck,black seabream has a close genetic relationship with glithead seabream,while in bck,black seabream has the closest genetic relationship with large yellow croaker and separates into another branch compared with other fishes.