Complete DNA sequence of the virulence plasmid in Rhodococcus equi

测定了马红球菌ATCC 33701毒力质粒pREAT701的全核苷酸序列。质粒含80608pb， GC含量65%。序列数据的计算机分析显示，毒力质粒编码67个开放阅读框（orf），占完整序列的73.5%。在67个orf中，37个orf与当前数据库中的任何已知蛋白都没有显著的同源性，其余30个orf与先前描述的假设蛋白具有显著的同源性；11种是未知的，19种是功能蛋白。我们之前报道过pREAT701携带一个毒力相关的15- 17 kda抗原（VapA）基因。在19个orf中，6个orf编码的蛋白质与VapA具有显著的相似性，位于位置1至21,000之间。GC含量为59%，低于21,001 ~ 80608位点的其余DNA序列（68%）和equi的染色体DNA（71%）。插入元件分散在整个质粒中，表明毒力质粒的镶嵌性质，并表明获得毒力基因的进化事件。

The complete nucleotide sequence of virulence plasmid pREAT701 from Rhodococcus equi ATCC 33701 has determined. This plasmid contained 80,608pb with 65% GC content. Computer analysis of sequence data revealed that the virulence plasmid encodes 67 open reading frames (ORFs), which occupied 73.5% of the complete sequence. Of the 67 ORFs, 37 ORFs had no significant homology to any known proteins in the current database and the remaining 30 showed significant homologies with previously described hypothetical proteins; 11 are unknown and 19 are functional proteins. We have previously reported that pREAT701 carries a virulence-associated 15- to 17-kDa antigen (VapA) gene. Of the 19 ORFs, 6 ORFs encode proteins that showed significant similarities to VapA, which located between positions 1 to 21,000. GC content is 59%, which is lower than those of the rest of the DNA sequence at positions 21,001 to 80608 (68%) and the chromosomal DNA of R. equi (71%). Insertion elements were scattered throughout the plasmid, indicating the mosaic nature of the virulence plasmid and suggesting evolutionary events by which virulence genes have been obtained.