鸡MYCN基因不同组织mRNA表达及其遗传多态性与免疫性状的关联分析

Analysis of mRNA Expression of MYCN Gene in Different Tissues and Genetic Polymorphisms Associated with Immune Traits in Chicken

为发掘与鸡免疫性状相关的分子标记,以大骨鸡为试验材料,采用半定量RT-PCR法对MYCN基因不同组织mRNA表达特性进行分析,并用PCR-SSCP方法对MYCN基因第2外显子的序列多态性进行检测,通过关联分析以期望发现与鸡免疫性状相关的单核苷酸变异。结果表明:鸡MYCN基因在心脏、肝脏、脾脏、肺、肾脏、卵巢、大脑和胸腺组织中均有表达,但其表达水平存在一定差异,其中,在胸腺和脾脏组织中的mRNA表达水平最高(P<0.05),在肺脏、肾脏、卵巢和大脑中的表达水平次之,在心脏和肝脏中的mRNA表达水平最低(P<0.05)。在MYCN基因第2外显子上检测到C2178T的转换,该多态性位点产生了3种基因型:AA、BB和AB,基因型频率分别为0.358、0.058和0.584,等位基因A和B的频率分别为0.65和0.35。对不同基因型的120只大骨鸡进行免疫性状关联分析表明,BB基因型个体的碱性磷酸酶含量显著高于AA型和AB型(P<0.05),其他血液生化免疫指标差异不显著(P>0.05);且BB基因型个体的红细胞含量和红细胞压积均显著高于AA型(P<0.05),其他免疫性状间的差异不显著(P>0.05),此研究结果为进一步筛查并验证MYCN基因可否作为抗病候选基因提供参考依据。

To explore the molecular Markers associated with chicken immune traits, having Dagu chicken as test materials, by semi-quantitative RT-PCR method,the expression of MYCN gene mRNA of different tissues was analyzed. By PCR-SSCP method, the genetic polymorphisms of MYCN gene was detected, and thus analyzed with immune traits associated. The results showed that： MYCN gene was expressed in heart, liver, spleen, lung, kidney, ovary, brain and thymus of chicken. Among them, the highest expression level of mRNA was in the spleen and thymus, followed by lung, heart, liver and ovary. This showed that chicken MYCN mRNA in vivo tissue was widely distributed, but the expression level was uneven. The results of PCR-SSCP showed that a variationC2178T was detected on conversion exon Ⅱ of MYCN gene, three genotypes were found： AA, BB, AB. Genotype frequencies ： 0. 358,0. 058,0. 584, allele frequencies ： A 0. 65, B 0. 35. Different enzyme genotypes and biochemical blood analysis showed an association： alkaline phosphatase levels of BB genotype were significantly higher than AA and AB （P 〈0.05） ; other blood biochemical enzyme content was not significant （P〉 0.05） ; different genotypes associated with some immune parameters showed that： levels of red blood cells and hematocrit of BB genotype were significantly higher than AA genotype （P 〈0. 05）; other immune parameters were not significant （P 〉0. 05）. The study provides reference data for further confirmation of MYCN gene as an ant-disease candidate gene.