黄鳝ghrelin基因的克隆及分子特征分析  

Cloning and Molecular Characterization of the Ghrelin Gene in the Rice-field Eel,Monopterus albus

作　　者：阮国良[1,2,3] 廖凯[1] 杨代勤[1,3] 邴旭文[2] 

机构地区：[1]长江大学动物科学学院,湿地生态与农业利用教育部工程研究中心,湖北荆州434025 [2]农业部淡水渔业和种质资源利用重点实验室,中国水产科学研究院淡水渔业研究中心,江苏无锡214081 [3]淡水水产健康养殖湖北省协同创新中心,湖北武汉430070

出　　处：《水生态学杂志》2016年第1期93-100,共8页Journal of Hydroecology

基　　金：湖北省自然科学基金(2013CFB393);农业部淡水渔业与种质资源利用重点实验室开放基金课题(KF201307);国家支撑计划课题(2013BAD20B06);湖北省支撑计划项目(2015BBA235);湖北省高等学校优秀中青年创新团队项目(T201503)

摘　　要：Ghrelin是联系生殖和能量代谢的重要桥梁信号分子,通过克隆黄鳝(Monopterus albus)的ghrelin基因并对其基因结构和功能进行了初步分析;运用c DNA末端快速扩增技术获得了黄鳝ghrelin基因的c DNA序列和DNA序列全长。结果表明,黄鳝ghrelin基因c DNA全长552 bp(Gen Bank accession no.JX122807),包括115 bp的5'端非编码区、324 bp的完整开放阅读框以及113 bp的3'端非编码区;DNA序列全长1323 bp,由3个内含子和4个外显子构成,内含子剪切位点具有典型识别核苷酸GT/AG,3个内含子分别为594 bp、84 bp和93 bp,4个外显子长度分别为229 bp、78 bp、112 bp和133 bp。氨基酸序列分析显示,ghrelin基因推导的Ghrelin蛋白前体原(propreghrelin)序列由26 aa的信号肽、19 aa的成熟肽以及C端氨基酸残基等构成;其中,成熟肽第3位为丝氨酸(Ser3),是Ghrelin的酰基化位点;C端氨基酸残基序列极可能包括与Ghrelin成熟肽功能相互拮抗的肥胖抑制素(Obestatin)。氨基酸的同源性及进化关系分析表明,黄鳝与某些鲈形目鱼类的蛋白前体原存在高度相似性,且在进化上黄鳝与较高级的鲈形目、鲽形目鱼类聚为一支。ghrelin基因结构及其蛋白质某些氨基酸残基序列的高度保守,预示着Ghrelin在脊椎动物中有着重要的生理功能与类似的作用机制。Ghrelin is an important signaling molecule for reproductive behavior and metabolism. The rice-field eel is a fresh water fish with natural sexual reversal from female to male via intersex,and is now widely used as a model animal in research of vertebrate sex determination and development. The ghrelin gene of Monopterus albus was cloned and the structure and function of the ghrelin gene were analyzed. The sequence of the ghrelin gene was determined at DNA and c DNA levels using rapid amplification of c DNA. The full-length of the ghrelin c DNA sequence was 552 bp（ Gen Bank accession no. JX122807）,consisting of a 115 bp 5＇-untranslated region,a 324 bp open frame and a 113 bp 3＇-untranslated region. The full-length of the ghrelin DNA sequence was 1 323 bp,consisting of three introns and four exons,and the exon / intron junctions were found to conform to the GT / AG rule.The sequences of the three introns were 594 bp,84 bp and 93 bp and the sequences of the four exons were 229 bp,78 bp,112 bp and 133 bp. Amino acid sequence analysis shows that the deduced propreghrelin sequence of M albus contains a 26 aa signal peptide（ SP）,a 19 aa mature peptide（ MP） and a C-terminal amino acid residue. Among them,the third amino acid（ Ser^3） of MP is the site for N-acylation and N-deacetylation,and the C-terminal amino acid residue likely includes an obestatin peptide,a physiological antagonist of the mature Ghrelin peptide.Homological and phylogenic analyses of amino acid sequences suggest that the propreghrelin of the rice-field eel has high similarity to those of Perciformes and,phylogenetically,the rice-field eel clusters with Perciformes and Pleuronectiformes. The highly conservative gene structure of ghrelin indicates that it has important physiological functions.

关 键 词：黄鳝 GHRELIN基因 克隆 分子结构 

分 类 号：Q175[生物学—水生生物学]