NOD基因牛结核病易感相关SNPs的鉴定及功能解析

Bovine tuberculosis is a serious infectious disease for both humans and animals, which is caused by Mycobacterium bovis. The study of bovine tuberculosis has been focused on the pathogen and environment. The studies of human tuberculosis found that, TB susceptibility was closely associated with single nucleotide polymorphism (SNPs), especially in the genes related to human innate immunity. NOD and its signaling pathway are very important for human and cattle by producing immune responses against Mycobacterium tuberculosis. This project will detect SNPs loci in the promoter region of NOD gene by using statistically analyze and DNA sequencing methods. Then detect the relevance of bovine tuberculosis to identify the high-risk of SNP loci and defect genotypes response for susceptibility to bovine tuberculosis. Furthermore, the molecular mechanism of these SNP loci affecting susceptibility to TB will be studied in vitro and in vivo, by using insect fluorescence reporter expression systems, EMSA methods and so on. Our studies will be useful to evaluate the molecular mechanism of these SNPs loci affecting susceptibility to bovine tuberculosis. At the same time, it will also provide a new way for breeding cattle with the genes resistant to bovine tuberculosis.

牛结核病是由牛型结核分枝杆菌引起的一种人兽共患传染病，近年来其研究多侧重于病原和环境方面。但人结核病的研究发现，结核易感性与宿主免疫应答相关基因的单核苷酸多态性（SNPs）密切相关。NOD及其信号通路是人和动物抗结核免疫应答的主导途径。本项目将首先通过DNA测序和统计学方法进行NOD基因启动子区域SNPs与牛结核病的关联研究，筛选出牛结核易感高风险SNPs位点及其缺陷基因型。然后通过荧虫酶报告表达系统等体外试验技术和EMSA等体内试验技术确定SNPs缺陷基因型基于NOD及其信号通路影响结核易感性的分子发病机理。本研究对于区分结核易感高风险牛群，掌握牛结核病的分子发病机理等都具有重要意义。同时，也为牛的抗病遗传育种提供一种新思路。

牛结核病是由牛型结核分枝杆菌引起的一种人兽共患传染病，近年来其研究多侧重于病原和环境方面。但人结核病的研究发现，结核易感性与宿主免疫应答相关基因的单核苷酸多态性（SNPs）密切相关。NOD及其信号通路是人和动物抗结核免疫应答的主导途径。本研究首先通过DNA测序和统计学方法进行NOD1和NOD2基因SNPs与牛结核病的关联研究，系统筛选出牛结核易感高风险SNPs位点及其缺陷基因型。然后通过生物信息学分析、体内体外试验等探讨了SNPs缺陷基因型基于NOD及其信号通路影响结核易感性的分子发病机理。研究结果表明，NOD1基因启动子区域G-1237T、外显子区域C338T、G1482C、G797A；NOD2基因外显子区域A2301G、C2306T与中国荷斯坦奶牛结核病易感性显著相关。进一步的分子生物学功能解析结果表明，NOD1基因启动子区域G-1237可能是一个比较强的易感高风险SNPs，能显著影响NOD1基因的表达量，继而影响下游信号通路中代表性免疫因子，如TNF-α、IFN-γ、IL-1β等的活化表达。NOD1基因外显子区域C338T、G1482C；NOD2基因外显子区域A2301G、C2306T可能影响NOD蛋白分子结构，继而影响牛结核病的易感性，值得进一步探讨。本研究对于区分结核易感高风险牛群，掌握牛结核病的分子发病机理等都具有重要意义。同时，研究也发现中国荷斯坦奶牛的SNPs开始具有了自己品系的特点，这些SNPs都有可能成为有用的基因分子标记，应用于抗病、提高奶品质、增加繁殖率等遗传育种领域。