The Polymorphism Of TLR2Gene And Correlation Study Of Bovine Tuberculosis Susceptibility

Bovine tuberculosis is caused by Mycobacterium bovis, the chronic consumptionof a zoonotic infectious diseases can be transmitted by sick animals to humans or otheranimals. Serious epidemic of bovine tuberculosis infection affecting the sustained andhealthy development of animal husbandry, more serious threat to human health. Thistopic from the molecular level study of bovine tuberculosis, to help people control anderadication of bovine tuberculosis, the test also lay the foundation for future research.Though testing tuberculosis on test-animals by use of PPD and ELISA method,this experiment detected the relevance of all the SNP in TLR2intact coding region andthe occurrence of bovine tuberculosis with PCR and DNA sequencing method andstatistics software, in order to discuss the molecular mechanism of SNP’s influence onthe susceptibility of bovine tuberculosis. This experiment is of great significance todifferentiating cattles which are highly susceptible to tuberculosis and to thoroughlyunderstanding the pathogenesis of bovine tuberculosis. Meanwhile, it could providenew ideas to preventing bovine tuberculosis and genetic breeding of cattle.1. Detect tuberculosis on test-animals with PPD and ELISA methodAfter detected tuberculin allergic reaction (PPD) and γ interferon (ELISA) to382cattles from livestock-farms in cities of Luoyang, Yiyang, Lankao and Nanyang inHenan province, the result showed that PPD detected11positive cases (with2suspected cases) accounting for2.36%, ELISA detected3positive cases making up1.29%, and PPD and ELISA detected2double positive cases accounting for1.28%.2. Segmently amplificate and sequence the TLR2gene in Yellow cattle by PCRmethod according to designed primers of TLR2gene sequence of cattle which werepublished on GenBank. The sequencing obtained the complete sequence of2399bp, containing completecoding region of TLP2,5’-and3’-non-coding region. Sequence analysis showed that,TLP2gene in Yellow cattle contain ORF of2355bp in length encoded784aminoacids.16bases of coding region of TLR2gene of Yellow cattle had changed comparedto that of Holstein,9in extracellular region,2in transmembrane region, and5inintracellular region, but none of amino acid changed. Comparing with TLR2genereference sequence of other animals published on GenBank, the homology rates ofnucleotide sequences of TLR2gene among Yellow cattle and Holstein cow, bisons,buffalo, sheep, goats, pigs, gorillas, human were respectively99.3%,99.3%,98.0%,96.3%,95.5%,85.4%,83.2%,83.1%. There is signal peptides at N’ end of TLR2andprobably a schizolysis site at21st amino acid place. The protein molecular structureprediction verify that TLR2protein has2transmembrane structure domain.3. Detect the polymorphism of TLR2gene as well as relevance of SNP locus andoccurrence ofbovine tuberculosis by means of statistics software, in order to ascertainhigh-risk SNP locus and its defect genotype of bovine tuberculosis. The result shows:(1) There are polymorphic loca (SNP) in TLR2in cattle.(2) In the studied SNPs loca,there are6SNP loca manifesting significant statistic difference with normal comparinggroup and remarkable relevance to bovine tuberculosis. The genotype on TLR2geneshows positive correlation with tuberculosis, which means they are high-riskingfactors and are closely related with the occurrence of bovine tuberculosis.