MMP-2和MMP-9基因在牦牛肌肉组织的表达分析

Expression analysis of MMP-2 and MMP-9 in yak muscle tissue

采用RT-PCR和DNA重组技术克隆牦牛基质金属蛋白酶MMP-2和MMP-9基因CDS区,检测0.5岁、1.5岁和2.5岁牦牛臀大肌和心脏组织中表达水平,作生物信息学分析。结果表明,①牦牛MMP-2和MMP-9基因CDS区长度分别为1983 bp和2137 bp,二者编码的蛋白质均为酸性亲水蛋白,无跨膜结构、含有多个磷酸化位点和糖基化位点;MMP-2与MMP-9主要分布区域不同;MMP-2为非典型分泌蛋白;MMP-2和MMP-9蛋白二级结构均以无规则卷曲为主;②牦牛MMP-2和MMP-9蛋白中甘氨酸、天冬氨酸和亮氨酸含量较高,此为牦牛肉质鲜美原因之一;③牦牛MMP-2和MMP-9基因序列与其他物种比对后,发现牦牛与黄牛亲缘关系最近,显示这两个基因可用于动物系统进化研究;④牦牛MMP-2和MMP-9基因在牦牛臀大肌和心脏组织中表达水平与年龄增长呈正相关。臀大肌组织免疫组化结果显示,MMP-2和MMP-9蛋白表达趋势与基因表达趋势相似,表明明胶类酶MMPs可能是肉质随年龄增大而改变的原因之一。

The CDS regions of MMP-2 and MMP-9 genes of yak matrix metalloproteinases were cloned by RT-PCR and DNA recombination technology,and these two genes mRNA expression in the gluteus maximus and heart tissues of 0.5,1.5 and 2.5 years old yak were detected and bioinformatics analysed.The results showed that①The CDS regions of the yak MMP-2 and MMP-9 genes were 1983 bp and 2137 bp,respectively.Both of them were acidic hydrophilic proteins,had no transmembrane structure,and contained multiple phosphorylation sites and glycosylation sites.MMP-2 was mainly distributed in the cytoplasm,but MMP-9 was mainly distributed in the extracellular area.MMP-2 was an atypical secreted protein.The secondary structures of MMP-2 and MMP-9 proteins were mainly random coils,respectively.②Yak MMP 2 and MMP 9 encoding proteins contained high levels of glycine,aspartic acid and leucine,which might be one of the main reasons for the deliciousness of yak meat.③The relationship between yak and cattle was the closest,but with other species the genetic relationship of the yak was relatively distant,which was consistent with previous research,showing that these two genes could be used in the study of animal systems evolution.④Expression level of yak MMP-2 and MMP-9 genes in yak gluteus maximus and heart was positively correlated with age.The results of immunohistochemical at gluteal muscle showed that the expression trends of MMP 2 and MMP-9 proteins were similar to the genes expression,indicating that gelatinase MMPs might be one of the reasons for the change of meat quality with age.