摘要
以长白猪(Landrace)大脑cDNA为模板,克隆长白猪黑皮质素受体3和4基因(MC3R和MC4R).序列分析显示:长白猪MC3R基因cDNA编码具319个氨基酸的前体蛋白,与人、大鼠、小鼠和斑马鱼的氨基酸序列一致性分别为86.4%、83.3%、82%和69.7%;MC4R基因cDNA全长1175bp,编码具332个氨基酸的前体蛋白,与人、大鼠、小鼠的氨基酸序列一致性高达94%以上,与斑马鱼MC4R氨基酸序列享有70.7%的同源性.序列分析显示,猪MC3R和MC4R基因都具有典型的七次跨膜结构域,和短的胞内环和胞外环,且在第五个跨膜域中保守的甲硫氨酸(M)分别替换为异亮氨酸(I)和缬氨酸(V).另外,在猪MC3R和MC4R中还鉴定到保守的半胱氨酸残基,第一个胞内环中保守的PMY基序和N末端的3个N-链接糖基化位点.组织表达图谱分析表明,MC3R主要在大脑和脾中高表达,而MC4R主要在六种检测的组织中都有表达,在肾中表达较弱.
Abstract. In this study, using eDNA of Landrace pig brain as the template, the full-length cDNAs of MC3R and MC4R genes have been cloned. Pig MC3R eDNA encodes a protein precursor of 319 amino acids, which shares high amino acid sequence identity with that of human (86. 4%), rat (83. 3%), mouse (82%) and zebrafish(69.7%). Pig MC4R eDNA is 1175 bp in length and encodes a protein pre- cursor of 332 amino acids, which shares high amino acid sequence identity (〉94%) with that of mam- mals and zebrafish(69.7 %). Further structural analyses indicate that pig MC3R and MC4R contain typi- cal seven transmembrane domains and short extracellular (ECL) and intracellular (ICL) loops. The sub- stitution of a methionine for isoleucine(MC3R)/ Valine(MC4R) in the fifth transmembrane domain (TMD 5) also has been identified. In addition, pig MC3R and MC4R share the PMY motif in the first ICL and 3 conserved N-linked glycosylation sites within N-terminal domain which are conserved in most MCRs. RT-PCR assay revealed that. MC3R is mainly expressed in brain and spleen with high abun- dance. While MC4R is expressed all six pig tissues examined with relatively weak signals in kidney.
出处
《四川大学学报(自然科学版)》
CAS
CSCD
北大核心
2013年第4期899-907,共9页
Journal of Sichuan University(Natural Science Edition)
基金
转基因生物新品种培育科技重大专项(2009zx08009-145B)