苏紫猪SLA-1基因多态性及其抗病潜能分析

Analysis on Polymorphism of SLA-1 Gene and Its Disease Resistance Potential in Suzi Pig

【目的】探究苏紫猪白细胞抗原-1(swine leukocyte antigen-1,SLA-1)基因多态性,并对其抗病潜能进行分析,以期为苏紫猪分子育种提供理论基础。【方法】以苏紫猪血细胞cDNA为模板,用PCR法扩增苏紫猪SLA-1基因并测序,利用DNAStar和Mega 5.0软件分别进行相似性分析及系统进化树构建;利用NetMHCpan 4.1 server分析SLA-1与非洲猪瘟病毒(African swine fever virus,ASFV)抗原表位结合的能力及特征;运用生物学软件对其编码蛋白的理化性质、亲/疏水性、跨膜区、结构和功能等进行预测。【结果】试验成功扩增6条苏紫猪SLA-1等位基因序列,分别为SLA-1*sz01、SLA-1*sz02、SLA-1*sz03、SLA-1*sz04、SLA-1*sz05和SLA-1*sz06,其高变异位点主要位于肽结合沟(peptide-binding groove,PBG)α1区和α2区;相似性比对结果显示,6条苏紫猪SLA-1等位基因核苷酸、氨基酸序列相似性分别在92.9%~96.9%、87.0%~94.8%之间,与不同品种猪核苷酸、氨基酸序列相似性分别在92.8%~98.8%、84.3%~98.0%之间;ASFV来源多肽结合能力的预测结果显示,SLA-1*sz01蛋白具有较强的ASFV抗原呈递能力,与ASFV来源B354L蛋白多肽片段FIDKTTVLY具有最高亲和力;SLA-1*sz01蛋白功能域及三级结构预测结果显示,SLA-1*sz01与免疫系统相关,具有经典的SLA-1三级结构。【结论】本研究扩增得到6条苏紫猪SLA-1基因序列,其中SLA-1*sz01能够限制性结合较多的ASFV来源抗原表位多肽,与多肽片段FIDKTTVLY具有最高亲和力,可作为苏紫猪抗病育种的候选基因。研究结果为ASFV疫苗的研发提供参考基础。

【Objective】The purpose of this study was to explore the genetic polymorphism of swine leukocyte antigen-1(SLA-1)and analyze its disease resistance potential,in order to provide a theoretical basis for molecular breeding of Suzi pig.【Method】The SLA-1 gene was amplified by PCR using blood cell cDNA in Suzi pig as a template and sequenced.Similarity analysis and phylogenetic tree construction were conducted using DNAStar and Mega 5.0 software,respectively.NetMHCpan 4.1 server was used to analyze the ability and characteristics of SLA-1 molecule binding to African swine fever virus(ASFV)antigenic epitopes.The physical and chemical properties,hydrophilic and hydrophobic properties,transmembrane region,structure and function of the encoded proteins were predicted by biological software.【Result】Six SLA-1 allele sequences of Suzi pig were successfully amplified,and namely SLA-1*sz01,SLA-1*sz02,SLA-1*sz03,SLA-1*sz04,SLA-1*sz05 and SLA-1*sz06.The highly variable sites were mainly located in theα1 andα2 regions of the peptide binding groove(PBG).The similarity comparison results showed that the similarity of the six SLA-1 alleles nucleotide and amino acid sequences of Suzi pig were between 92.9%to 96.9%and 87.0%to 94.8%,respectively.The similarity of the six SLA-1 alleles nucleotide and amino acid sequences of Suzi pig with different pig breeds were between 92.8%to 98.8%and 84.3%to 98.0%,respectively.The prediction results of the binding ability of ASFV derived polypeptides showed that the SLA-1*sz01 protein had a strong ASFV antigen presentation ability,and had highly affinity with B354L protein polypeptide fragment FIDKTTVLY in ASFV.Prediction of functional domain and tertiary structure showed that SLA-1*sz01 was related to the immune system and had a classic SLA-1 tertiary structure.【Conclusion】In this study,six SLA-1 gene sequences were obtained,among which SLA-1*sz01 could restrict the binding of more ASFV-derived peptides,and had the highest affinity with FIDKTTVLY,which could be used as a candidate gene for disease resistance breeding of Suzi pig.The results provided a reference basis for the research and development of ASFV vaccine.