马身猪MEF2A基因4种可变剪接体的克隆和生物信息学分析

本研究旨在克隆马身猪肌细胞增强因子2A（myocyte enhancer factor 2A，MEF2A）基因的不同剪接体类型。依据转录组测序对可变剪接的预测结果，试验扩增MEF2A基因第5~8外显子之间的编码区，用生物信息学软件分析了马身猪MEF2A基因不同剪接体的序列特性，预测保守结构域，构建系统进化树，比对不同物种MEF2A的氨基酸同源性。结果显示，获得了4个MEF2A基因的剪接体，MEF2A1的第5~8外显子正常剪接；MEF2A2缺失了第5外显子，第6外显子的5'端多出138 bp，第7外显子的3'端多出102 bp；MEF2A3缺失了第5外显子，第6外显子的5'端多出138 bp；MEF2A4第7外显子的3'端多出102 bp。插入的138 bp序列编码的蛋白质中存在1个保守结构域HJURP_C，这可能与MEF2A参与肝细胞纤维化作用有关。MEF2A1和MEF2A4与猪MEF2A1（GenBank登录号:NP_001090890.1）同属于一个亚群，同源性高达98.9%，MEF2A2和MEF2A3与猪MEF2A2（GenBank登录号:NP_001093168.1）同属于一个亚群，同源性分别为98.2%和98.9%。本试验成功克隆了4个MEF2A基因的剪接体，为进一步研究其蛋白功能奠定基础。

Cloning and Bioinformatics Analysis of 4 Alternative Splice Variants of MEF2A Gene in Mashen Pig

This study was aimed to clone the different splicing variants of myocyte enhancer factor 2A (MEF2A) gene in Mashen pig. According to the prediction results of the alternative splicing in the RNA-Seq sequencing, the coding region of MEF2A gene exons 5-8 were amplified. We analyzed the sequence characteristics of different splicing variants of MEF2A gene in Mashen pig, predicted conservative structure domain, constructed phylogenetic tree and compared the homology of MEF2A amino acid in different species by bioinformatics softwares. The results showed that 4 alternative splice variants of MEF2A gene were obtained. The exons 5-8 of MEF2A1 spliced normally. MEF2A2 lacked the exon 5, and the 5'end of exon 6 was 138 bp longer, the 3'end of exon 7 was 102 bp longer. MEF2A3 lacked exon 5, and the 5'end of exon 6 was 138 bp longer. The 3'end of MEF2A4 exon 7 of was 102 bp longer. The protein, encoded by inserted 138 bp sequence, contained a conserved domain-HJURP_C, which was the result of MEF2A participating in hepatocyte fibrosis. The MEF2A1, MEF2A4 and MEF2A1 of pig submitted in GenBank (accession No.NP_001090890.1) belonged to a subgroup, homology up to 98.9%. The MEF2A2, MEF2A3 and MEF2A2 of pig submitted in GenBank (accession No.NP_001093168.1) belonged to a subgroup, the homology was 98.2% and 98.9%, respectively. The successful cloning of 4 alternative splice variants of MEF2A gene laid the foundation for further study on the function of MEF2A protein.