奶牛乳腺炎无乳链球菌临床分离株fbsA基因的克隆与序列分析

目的克隆并分析牛乳腺炎无乳链球菌内蒙古地区临床分离株表面蛋白fbsA基因核苷酸及编码氨基酸序列,预测其潜在的抗原表位。方法以无乳链球菌内蒙古地区临床分离株为材料,根据GenBank中公布的无乳链球菌fbsA基因序列设计特异性克隆引物,采用同源克隆法,PCR扩增fbsA基因序列,采用DNA Star生物信息学软件预测分析其编码氨基酸的潜在抗原性。结果克隆的fbsA基因序列大小为321bp,编码107个氨基酸残基,与GenBank中公布的B群无乳链球菌fbsA基因核苷酸序列同源性为98.13%,氨基酸序列同源性为99%。预测克隆基因编码氨基酸抗原性指数良好。结论成功克隆出内蒙古地区奶牛乳腺炎无乳链球菌表面蛋白fbsA基因序列,并预测其编码氨基酸具有潜在抗原性为进一步研究其原核表达产物的抗原性及致病机制奠定了基础。

Cloning and sequencing of the fbsA gene of a bovine Streptococcus agalactiae strain from Inner Mongolia

Objective The fbsA gene of a bovine Streptococcus agalactiae strain was cloned,its nucleotides and amino acids were sequenced,and its potential epitopes were predicted. Methods A pair of special primers was designed for PCR from genomic DNA according to the sequences of the fbsA gene of S.agalactiae published on GenBank.fbsA gene sequences were amplified using PCR.A partial sequence of the fbsA gene was cloned and sequenced.The potential antigenicity of the amino acids that it encoded was predicted using DNA Star bioinformatics software. Results Sequencing indicated that this fragment was 321bp in size and that it encoded 107amino acids.The gene had 98.13%similarity to the fbsA gene from S.agalactiae（group B Streptococcus,AJ437622.1）published on GenBank,and amino acid sequences had 99%similarity.The predicted results indicated that the cloned gene encoding amino acids had an acceptable antigenic index. Conclusion The fbsA gene of bovine S.agalactiae from Inner Mongolia was successfully cloned and its potential antigenicity was predicted.This has established a basis for further study of its expression and analysis of its antigenicity.