不同发育阶段蒙古牛肌肉组织差异表达基因的筛选

摘要

In order to find the genetic mechanism which impact on the meat quanlity in different development stages of bovine at the molecular levels, we used mRNA differential display reverse-transcription PCR (DDRT-PCR) to identify differentially expressed genes in different development stages of bovine skeletal muscles. A total of 6 ESTs were found and subsequently compared with the nucleotide sequences in GenBank database using BLAST. SI was highly similar to the bovine coffilin 2 (CFL2) gene, the others(S2 to S6) were no significant similarity with existing genes or ESTs and were reguarded as the new EST. The mRNA expression of CFL2 gene was examined by relative quantitative PCR. The results indicated that the expression of CFL2 of 5 years old Mongolia bovine's muscle tissue was 3. 8 times more than 16 months old one's. It was well known that the excessive expression of CFL2 could inhibit G-actin polymerization and accumulation of high quality type 1 muscle fiber, therefore, it demonstrated that the high expression of CFL2 gene might cause decline of the meat traits of Mongolia bovine.%应用mRNA差异显示技术,对两个发育阶段(16月龄和5岁龄)蒙古牛臀肌组织差异表达的基因进行研究,从分子水平分析影响不同发育阶段蒙古牛肉品质的遗传机制.经mRNA差异筛选获得6条差异表达的EST片段,与GenBank中序列进行相似性比对后发现,其中一条序列S1与牛的丝切蛋白2 (cofilin 2,CFL2)基因高度同源(相似性99％),确认S1就是牛的CFL2基因；另外5条S2- S6在数据库中未发现同源序列,确定为新的EST片段.采用相对定量PCR方法对差异表达基因CFL2进行真实性鉴定和差异表达量检测,结果显示,CFL2基因在5岁龄蒙古牛肌肉组织中的表达量是16月龄的3.8倍.过量的丝切蛋白2可以抑制单体型肌动蛋白的聚合及1型优质肌纤维的累积,其高表达可能导致了蒙古牛肉质性状的下降.