猪MEF2a基因的克隆与表达

Cloning and Expression of Porcine MEF2a Gene

为了进一步了解猪MEF2a基因的结构与功能,本研究采用生物信息学结合RT-PCR的方法,克隆了猪的MEF2a基因,获得了它的2个变异体序列。结果表明,猪MEF2a variant 1基因cDNA长1 524 bp(EF576923),编码508个氨基酸,分子量为54.481 ku;variant 2基因cDNA长1 416 bp(EF576922),编码471个氨基酸,分子量为50.846 ku。MEF2a两个变异体的氨基酸序列同源性为86.79%,第1aa^77aa和第132aa^470aa完全一致,第78aa^131aa是高变区,variant2与variant1相比,在第224aa^258aa处存在34个氨基酸(102 bp)的缺失。利用Real-ti me PCR方法检测了MEF2a的表达。结果表明,MEF2a mRNA是一个广谱表达基因,在心、肝、胃、脾、肾、肺、大肠、小肠、背肌和腿肌中都能检测到,在腿肌中优势表达。MEF2a variant1与马和家鼠构成一个小类群,而variant 2与牛和人构成了另外一个小类群,推测MEF2a基因在进化过程中发生了较为明显的变异。

In order to understand the structure and function of porcine MEF2a gene, porcine MEF2a gene was cloned by bioinformatics and RT-PCR, and two variant sequences were obtained. Variant 1 （1 524 bp, EF576923） encodes 505 amino acids which is 54. 481 ku. Variant 2 （1 416 bp, EF576922） encodes 471 amino acids which is 50. 846 ku. Amino acid sequence homology between MEF2a variants is 86. 79%. It is completely identical in 1st - 77th and 132th - 470th amino acids, and is hypervariable in 78th-131th region. Variant 2 has 34 amino acids （102 bp） deletion in 224th-258th compared with variant 1. MEF2a mRNA is a broad-spectrum expression gene. It was detected in heart, liver, stomach, spleen, kidney, lung, large intestine, small intestine, dorsal muscle and leg muscle, especially superior expression in leg muscle by Real-time PCR. It was showed that in phylogentic tree, for variant 1, horse and house mouse was clustered one group and for variant 2, cattle and human was clustered another group. So it was presumed that MEF2a gene undergoes apparent variation during evolutionary process.