藏鸡诱导型一氧化氮合酶基因低氧适应功能分析

低氧刺激诱导型一氧化氮合酶(Inducible nitric-oxide synthase, iNOS)催化产生NO, 增加血流, 改善组织供氧。文章采用测序和PCR-RFLP技术检测藏鸡及低地鸡iNOS基因编码区、5′侧翼区(2.0 kb片段)序列和3′侧翼序列SNP, 并测定低氧和常氧孵化时鸡胚尿囊绒毛膜组织iNOS基因表达量和酶活力。结果在iNOS基因 5′侧翼区发现一个与低氧适应相关的藏鸡高频率突变SNP位点(-870C→T), 藏鸡该突变的等位基因T频率高于低地鸡种。藏鸡iNOS基因表达量和酶活力在低氧孵化环境中多高于矮小鸡。结果表明藏鸡群体iNOS基因的突变及其低氧表达量的增加是其适应低氧环境的重要基础。

Function of inducible nitric oxide synthase on adaptability to hypoxia in Tibetan chicken

The inducible nitric-oxide synthase (iNOS) can be induced by hypoxia to produce NO, which regulates blood flow and improves oxygen delivery to tissues. In present study, SNPs in coding and 5′-flanking regions of iNOS gene were examined in Tibetan chicken and lowland chicken using sequence and PCR-RFLP methods, and the quantitive express of mRNA of iNOS and the enzyme activity were measured in chorioallantoic membrane of chick embryo that was incubated under hypoxic and normal conditions. The results showed that a special SNP (-870C→T)was found in 5′-flanking region of iNOS gene. Tibetan chicken has higher frequencies in mutation allele T than lowland chicken. In hypoxic incubation, the mRNA expression of iNOS and enzyme activity were higher in Tibetan chicken than that in Dwarf chicken. It was con-cluded that the mutation of iNOS and hypoxic increase of its expression were important base for adaptability to hypoxia in Tibetan chicken.