新疆褐牛Toll样受体基因(TLR4)外显子Ⅲ2021位点突变与奶牛体细胞评分的相关性研究  

Association the Mutation of 2021 Locus of Toll-like Receptor 4 Gene (TLR4) Exon Ⅲ Polymorphisms with Somatic Cell Score in Xinjiang Brown Cattle

作　　者：林嘉鹏[1] 白杰[1,2] 张雪梅[1] 谭立新[1] 季生林 李文蓉[1] 刘明军[1] 

机构地区：[1]新疆畜牧科学院农业部家畜繁育生物技术重点开放实验室,新疆畜牧科学院生物技术研究中心,乌鲁木齐830000 [2]新疆大学生命科学与技术学院,乌鲁木齐830046 [3]新疆褐牛繁育中心,乌鲁木齐830049

出　　处：《农业生物技术学报》2010年第6期1115-1122,共8页Journal of Agricultural Biotechnology

基　　金：国家重点基础研究发展规划(973)前期专项(No2007CB116304)资助

摘　　要：Toll-样受体(tolllike receptors,TLRs)可以通过识别病原微生物启动天然免疫并激活适应性免疫。以中国荷斯坦奶牛和新疆褐牛为研究对象,对TLR4基因外显子3进行了序列分析,并对发现的多态性位点进行PCR-RFLP分析,共发现TLR4E3+1656、TLR4E3+2021和TLR4E3+2414三个多态位点。对TLR4E3+1656和TLR4E3+2021位点χ2检验表明:2个品种的突变均处于Hardy-Weinberg平衡状态(P>0.05)。运用最小二乘法分析表明,TLR4E3+1656位点的各基因型个体间的体细胞评分(SCS)差异不显著(P>0.05);而TLR4E3+2021位点中AA与AB基因型SCS水平差异显著(P<0.05),AA与BB基因型SCS水平差异极显著(P<0.01),但AB与BB基因型SCS水平差异不显著(P>0.05)。研究结果提示,TLR4E3+2021位点的AA基因型可能与抗乳房炎的抗性有关,A等位基因是乳房炎抗性的有利基因。采用RT-PCR技术检测了不同基因型的新疆褐牛个体中TLRs信号通路下游的部分基因mRNA的表达水平,结果显示,NF-κB1、NF-κB2和IL-1β基因mRNA表达水平与TLR4E3+2021位点AB和BB两种基因型差异显著(P<0.05),TLR4、IL-10和IL-8基因mRNA表达水平与TLR4E3+2021位点AB和BB两种基因型差异不显著(P>0.05)。Toll like receptors （TLRs） recognize pathogen ligands and mediates signaling to initiate innate and adaptive immune responses. In this experiment, Chinese holstei and XinJiang brown cattle were used as experimental example. Their genetic polymorphisms of TLR4 gene exon Ⅲ were detected by sequencing first and by PCR-RFLP in the second. Results showed that three poiymorphism loci, TLR4 E3＋1656, TLR4 E3＋2021 and TLR4 E3＋2414,were discovered. Statistical results of χ2 test indicated that two polymorphism sites （TLR4 E3＋1656 and TLR4 E3＋2021） in the three populations fitted with Hardy-Weinberg equilibrium（P0.05）. The associations were observed between genotypes and SCS by the least square analysis. The results showed that SCS was not significantly affected by different genotypes in TLR4 E3＋1656 （P0.05）; the significant different effect between genotype AA and AB was found （P0.05）, the difference was significant between genotype AA and BB was found （P0.01） and no significant difference were detected between genotype AB and BB（P0.05） in TLR4 E3＋2021 site. In conclusion, the AA genotype in TLR4 E3＋2021 site may be the best genotype to resist mastitis, the allele A may play an important role in mastitis resistance in bovine. To research the effect of different genotypes of TLR4 E3＋2021 site on SCS, part of the mRNA of the gene expression where in TLRs signaling pathway downstream of Xinjiang brown cattle were detected by Real-Time PCR. The level of Nuclear Factor-kappa b1（NF-κB1）, Nuclear Factor-kappa b2（NF-κB2） and Interleukin-1β（ IL-1β） transcripts was significantly correlated with genotype of AA and BB in TLR4 E3＋2021 （P0.05）, but the level of TLR4, IL-10 and IL-8 transcripts was no significantly correlated with genotype of AA and BB in TLR4 E3＋2021（P0.05）.

关 键 词：新疆褐牛 Toll样受体4(TLR4)基因 基因型 定量PCR 奶牛乳房炎 体细胞评分 

分 类 号：S823.912[农业科学—畜牧学]