黄鳝β-肌动蛋白基因的克隆及序列分析

Cloning and sequence analysis of cDNA encoding β-actin from rice field eel Monopterus albus Zuieuw

采用RT-PCR和RACE法,从黄鳝(MonopterusalbusZuieuw)肝脏中分离和克隆黄鳝β-肌动蛋白(actin)基因。该基因cDNA全长1765bp[不包括poly(A)],5'端非翻译区12bp,3'端非翻译区有625bp[不包含poly(A)],阅读框(Openreadingframe,ORF)1128bp,翻译成375个氨基酸,蛋白质分子量41 77kD。将所得序列与各科鱼、蛙、鸡、牛、鼠、人等的β-肌动蛋白基因序列同源性分析显示,核苷酸序列具有68%～95%的相似性,氨基酸序列具有97%～100%相似性,显示该基因在生物进化过程中的保守;系统发育分析表明黄鳝β-肌动蛋白基因与罗非鱼的亲缘关系最近。

actin is an important component of cytoskeleton and sarcomere. It plays important roles in many biological processes. Because its expression is stable during the development,it is usually used as internal standards of quantitative RT-PCR .A cDNA encoding β-actin is derived from the rice field eel (Monopterus albus Zuieuw) liver tissue using RT-PCR and RACE methods. The cDNA is 1765bp with 12bp 5’UTR,625bp 3’UTR(excluding poly(A)) and 1128bp ORF,which encodes 375 amino acids and has a predicted molecular weight of 41.77kD. Sequence analysis reveals the identity rate of β-actin cDNA nucleotide sequence between the rice field eel and Tilapiamossambica,Salmo salar,Oryzias latipes,Oncorhynchus mykiss,Danio rerio,Carassius auratus,Physalaemus pustulosus,Bos taurus,Gallus gallus,Mus musculus,Homo sapiens are 68%-95%;and the similarity of β-actin amino acid sequence is 97%-100%.This suggests β-actin is highly conserved.The phylogenetic tree constructed on the basis of β-actin nucleotide sequence suggests that the relationship of β-actin gene between rice field eel and Tilapia mossambica is the most intimate.