牦牛解偶联蛋白 3基因的克隆测序和肌肉表达谱

为了比较高原牦牛和低海拔地区黄牛解偶联蛋白-3(UCP3)基因序列及其在骨骼肌中的表达水平,采用RT-PCR方法从牦牛背最长肌中克隆UCP3基因,所获得的cDNA序列编码区及推导的氨基酸序列与GenBank中黄牛相应序列相比相似度均为99.04%,编码区有9个碱基差异,并导致3个氨基酸的改变。实时定量RT-PCR分析显示,牦牛背最长肌中UCP2 mRNA水平显著高于黄牛,而背最长肌中UCP3 mRNA及股二头肌中UCP2、UCP3 mRNA水平均显著低于黄牛。另外,牦牛背最长肌中Mn-SOD活力显著高于黄牛。这些特征可能与牦牛肌肉在低氧环境中的能量代谢有关。

Cloning and Sequencing and Muscle Expression Profile of Uncoupling Protein 3 in Yak

To compare gene sequence and mRNA level of the uncoupling protein 3 (UCP3) in skeletal muscles of plateau living yak and low altitude living cattle, UCP3 gene was successfully cloned from longissimus muscle of yak by RT PCR, and both the coding sequence of cDNA and deduced amino acid sequence share 99.04% homology with those of cattle from GenBank. There are nine nucleotide differences in coding sequence of UCP3 cDNA between yak and cattle, resulting in three amino acid differences. Real time quantitative RT PCR analysis showed that UCP2 mRNA level in longissimus muscle of yak was significantly higher than that of cattle, while UCP3 mRNA level in longissimus muscle, as well as UCP2 and UCP3 mRNA levels in biceps femoris of yak were significantly lower than those of cattle. Enzyme activity assay showed that Mn SOD activity in longissimus muscle of yak was significantly higher than that of cattle. These characteristics might be associated with energy metabolism of yak muscle in the hypoxic environment.