Takai S, Hines S A, Sekizaki T, Nicholson V M, Alperin D A, Osaki M, Takamatsu D, Nakamura M, Suzuki K, Ogino N, Kakuda T, Dan H, Prescott J F
Department of Animal Hygiene, School of Veterinary Medicine and Animal Science, Kitasato University, Towada, Aomori 034-8628, Japan.
Infect Immun. 2000 Dec;68(12):6840-7. doi: 10.1128/IAI.68.12.6840-6847.2000.
The virulence plasmids of the equine virulent strains Rhodococcus equi ATCC 33701 and 103 were sequenced, and their genetic structure was analyzed. p33701 was 80,610 bp in length, and p103 was 1 bp shorter; their sequences were virtually identical. The plasmids contained 64 open reading frames (ORFs), 22 of which were homologous with genes of known function and 3 of which were homologous with putative genes of unknown function in other species. Putative functions were assigned to five ORFs based on protein family characteristics. The most striking feature of the virulence plasmids was the presence of a 27,536-bp pathogenicity island containing seven virulence-associated protein (vap) genes, including vapA. These vap genes have extensive homology to vapA, which encodes a thermoregulated and surface-expressed protein. The pathogenicity island contained a LysR family transcriptional regulator and a two-component response regulator upstream of six of the vap genes. The vap genes were present as a cluster of three (vapA, vapC, and vapD), as a pair (vapE and vapF), or individually (vapG; vapH). A region of extensive direct repeats of unknown function, possibly associated with thermoregulation, was present immediately upstream of the clustered and the paired genes but not the individual vap genes. There was extensive homology among the C-terminal halves of all vap genes but not generally among the N-terminal halves. The remainder of the plasmid consisted of a large region which appears to be associated with conjugation functions and a large region which appears to be associated with replication and partitioning functions.
对马红球菌强毒株马红球菌ATCC 33701和103的毒力质粒进行了测序，并分析了它们的遗传结构。p33701长度为80,610 bp，p103短1 bp；它们的序列几乎相同。这些质粒包含64个开放阅读框（ORF），其中22个与已知功能的基因同源，3个与其他物种中功能未知的假定基因同源。根据蛋白质家族特征为5个ORF赋予了假定功能。毒力质粒最显著的特征是存在一个27,536 bp的致病岛，其中包含7个毒力相关蛋白（vap）基因，包括vapA。这些vap基因与vapA具有广泛的同源性，vapA编码一种温度调节的表面表达蛋白。致病岛在6个vap基因的上游包含一个LysR家族转录调节因子和一个双组分反应调节因子。vap基因以三个一组（vapA、vapC和vapD）、两个一组（vapE和vapF）或单个（vapG；vapH）的形式存在。在成簇和成对基因的紧邻上游存在一个功能未知的广泛直接重复区域，可能与温度调节有关，但单个vap基因上游不存在。所有vap基因的C端一半之间存在广泛的同源性，但N端一半之间通常不存在。质粒的其余部分由一个似乎与接合功能相关的大区域和一个似乎与复制和分配功能相关的大区域组成。
