鸭瘟病毒UL24基因的分子特征分析

Analysis of molecular characteristics of duck plague virus UL24 gene

根据本实验室获得的鸭瘟病毒的一段基因序列设计引物，利用PCR扩增UL24基因并克隆到pMD18-T载体，阳性重组质粒进行酶切鉴定、测序验证与生物信息学分析。结果显示，获得的UL24基因全长1230bp，编码409个氨基酸；与其他26株疱疹病毒科中α-疱疹病毒亚科的UL24基因的相似性较β和γ亚科高，其中与α亚科禽疱疹病毒属中的GaHV-3相似性最大（34．7％）；遗传进化树显示，该基因编码的蛋白与火鸡疱疹病毒的UL24蛋白的亲缘性最近。该蛋白是一种保守但不含信号肽的外膜蛋白，具有5个潜在的N-糖基化位点和19个磷酸化位点；编码的氨基酸Ala，Apn，Glu，Phe，Leu，Arg，Thr，Val具有一定的偏嗜性。二级结构分析显示，α螺旋和无规卷曲含量高，均达46．94％，而口折叠仅占6．11％；同源建模比对，未发现与之匹配的三级结构；预测的抗原表位主要位于肽链第36～48、241～323、344～379位区段。

According to UL24 gene sequence of duck plague virus（I）PV） isolated by the Key Laboratory of Animal Diseases and Human Health of Sichuan Province, a pair of primer was designed. The full length UL24 gene was amplified by PCR and cloned into pMD18-T vector. The positive plasmid was identified by digestion with restriction enzymes（EcoR Ⅰ ＋Xho Ⅰ ） and sequencing. Then, the DPV UL24 gene was analyzed by bioinformatics tools. The results showed that the sequence of UL24 gene was 1 230 bp,encoding 409 amino acids and had more homologous with UL24 genes of alpha herpesvirus subfamily than with those of beta and gamma subfamily of 26 strains other Herpesviridae,and it was closest genetically with poultry alpha herpesvirus（34.7 %）. Phylogenetic studies demonstrated that DPV UL24 protein was more closely related to that of turkey herpesvirus. The prediction results showed that UL24 protein may be an outer membrane protein, containing a conserved domain without signal peptide, and having 5 potential N-glycosylation sites and 19 phosphorylation sites. Codon bias analysis showed that UL24 gene was biased in some codons,especially those codons encoding amino acids Ala, Apn, Glu, Phe, Leu, Arg, Thr and Val.The secondary structure prediction showed that the alpha helix,random coil and beta sheet were 46.94%,46.94% and 6.11% ,respectively. The tertiary structure had not been gained by the way of Mock construction of molecular confirmation. The main antigenic epitopes of UL24 protein might be adjacent to the amino acid residues at 36-48,241-323 and 344-379.