鱼类谷胱甘肽转移酶基因cDNA克隆及其序列分析  

Cloning and the sequence analysis of the fish glutathione transferase Pi gene

作　　者：孙玉华[1] 谢平[2] 郭海涛[1] 夏文伟[1] 

机构地区：[1]华中农业大学水产学院,农业动物遗传育种与繁殖教育部重点实验室,武汉430070 [2]中国科学院水生生物研究所淡水生态与生物技术国家重点实验室,武汉430072

出　　处：《遗传》2007年第3期349-354,共6页Hereditas（Beijing)

基　　金：国家自然科学基金(编号:30530170);华中农业大学科研启动基金(编号:52204-04031);华中农业大学大学生科技创新基金资助~~

摘　　要：采用RT-PCR方法,从鲢、鲤、鲫3种鱼类肝脏总RNA中克隆出了谷胱甘肽转移酶Pi型(GST Pi)cDNA序列,推导了其编码的氨基酸序列。3种鱼类GST Pi的ORF全长627bp,编码208个氨基酸。翻译起始密码均为ATG,终止密码子均为TGA。鱼类与哺乳动物、两栖类爪蟾以及节肢动物丝虫之间GST Pi氨基酸序列相似度平均值分别为50%、33%、15%左右。5种鱼类之间的氨基酸序列相似度较大,其中鲤科鱼类之间平均为85%左右。我们以GST Pi为分子标记,用最大简约数法(MP)构建了13个物种的系统进化树,识别出两个大的单系类群:哺乳类组成类群一(bootstrap100);鱼类组成类群二(bootstrap93)。通过比较鱼类与哺乳类GST Pi N末端和C末端功能域的氨基酸组成差异,探讨了淡水鱼类GSTs承担较强的微囊藻毒素去毒能力的可能分子机制。Using RT-PCR method, the glutathione transferase Pi cDNAs were cloned from Cyprinus carpio, Hypophthalmichthys molitrix, and Carassius auratus. The open reading frames （ORFs） from the 3 fishes were 627 bp long （encoding for 208 amino acids） with the initial code ATG and the terminal code TGA. The sequence similarity was 50% between fish and mammals, 33% between fish and amphibian, and 15% between fish and arthropoda, respectively. The sequence similarity was big among fishes, and the average value of the 4 cyprinids was about 85%. Phylogenetic tree was constructed for 13 species based on GST Pi amino acid sequences using MP （Maximum Parsimony） method. Two major clusters were recognized： cluster one consisted of Mammals （bootstrap 100） and cluster two consisted of fishes （bootstrap 93）. Based on the sequences analyses of N/C domain of GST Pi, we proposed the detoxification mechanism of freshwater fishes that were thought to have stronger tolerance to microcystins.

关 键 词：谷胱甘肽转移酶Pi型 鲢 鲤 鲫 

分 类 号：Q78[生物学—分子生物学]