猪圆环病毒2型广西株的分离和全基因组序列分析

Isolation and Complete Genomic Sequence Analysis of Porcine circovirus Type 2 GXB Strain

从广西表现为断奶仔猪多系统衰竭综合征的猪群中分离到1株猪圆环病毒2型（PCV-2），命名为GXB株。对GXB株的全基因组进行PCR扩增，扩增产物克隆至PMD18-T载体。测序结果表明，全基因组为1767bp，与GenBank上已知的8株PCV-2参考株序列的同源性在95．0％～99．6％之间。序列分析表明，GXB株基因组包含11个读码框（ORF），其中ORF1和ORF2是最主要的读码框，分别编码314个和233个氨基酸，与其他PCV-2毒株的ORFl、ORF2氨基酸的同源性分别为97．8％～100％、91．5％～98．7％。对GXB株ORF2编码的Cap蛋白基因进行功能分析，表明含有1个潜在的糖基化位点，3个明显的亲水区，有较强的抗原性和亲水性，为作为主要的免疫原性蛋白基因提供了依据。

One porcine circovirus type 2（PCV2） strain was isolated from pigs which showing signs of postweaning muhisystemie wasting syndrome（PMWS） in Guangxi. It was denominated GXB. The complete genome of GXB wsa amplified with PCR. The PCR products were inserted into PMD18-T vector and were sequenced. The sequenced results showed that the complete genome are 1767 bp, the nucleotide homology were 95.0-99.6% compared with other PCV2 sequences published in GenBank. The complete genome of GXB includes 11 open reading frame（ORF）, ORF1 and ORF2 are the most important and encode 314 and 233 amino acids, respectively. The amino acids homologies of the ORF1 and ORF2 of GXB are 97. 8%- 100% and 91.5%-98.7% compared with that of other PCV2 strains. Function analysis of Cap protein encoded by ORF2 of GXB showed that, this protein contains one glycosylation site and three hydrophilic regions, has good hydrophilicity and antigenicity, and this gene product is the main pathogenic gene.