Ozawa Yutaka, Kawamori Fumihiko, Masuda Takashi, Masuzawa Toshiyuki, Fujita Hiromi, Ohashi Norio
Laboratory of Microbiology, Department of Food and Nutritional Sciences, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka and Global COE Program, Shizuoka 422-8526, Japan.
Department of Microbiology, Shizuoka Institute of Environment and Hygiene, Shizuoka, Japan.
J Med Microbiol. 2009 Dec;58(Pt 12):1638-1644. doi: 10.1099/jmm.0.011775-0. Epub 2009 Aug 27.
Anaplasma phagocytophilum, an agent of human granulocytic anaplasmosis, infects neutrophils and causes an emerging tickborne febrile disease. The genome of this bacterium contains a large number of p44/msp2-related genes encoding 44 kDa major outer-membrane proteins, and it is known that a specific p44/msp2 gene is predominantly transcribed from a single expression locus. This study successfully characterized the genomic expression site for p44/msp2 (3.8 kb) in uncultured A. phagocytophilum from Ixodes persulcatus ticks inhabiting a northern part of Japan. Comparative analysis of the sequences revealed that the structures of the expression sites in Japanese A. phagocytophilum were similar to those of US strains from human patients and European strains from a dog and sheep, but omp-1N (upstream from p44/msp2) and a truncated recA (downstream from p44/msp2) in the p44/msp2 expression site seemed to share similarities with those of US and European strains. The central hypervariable region sequences of Japanese p44/msp2 were found to be quite diverse (24.4-100 % amino acid similarities) and distinct from their closest relatives from US human patients or animal host origins (56.3-97.6 % amino acid similarities) with some exceptions. Thus, this study provides significant information about the molecular characteristics of A. phagocytophilum in East Asia, as well as the global diversity of p44/msp2.
嗜吞噬细胞无形体是人类粒细胞无形体病的病原体，可感染中性粒细胞并引发一种新出现的蜱传发热性疾病。该细菌的基因组包含大量编码44 kDa主要外膜蛋白的p44/msp2相关基因，并且已知特定的p44/msp2基因主要从单个表达位点转录。本研究成功鉴定了来自日本北部全沟硬蜱体内未培养的嗜吞噬细胞无形体中p44/msp2（3.8 kb）的基因组表达位点。序列比较分析表明，日本嗜吞噬细胞无形体中表达位点的结构与来自人类患者的美国菌株以及来自狗和羊的欧洲菌株相似，但p44/msp2表达位点中的omp - 1N（p44/msp2上游）和截短的recA（p44/msp2下游）似乎与美国和欧洲菌株具有相似性。日本p44/msp2的中央高变区序列被发现差异很大（氨基酸相似性为24.4 - 100%），并且与来自美国人类患者或动物宿主来源的亲缘关系最近的序列不同（氨基酸相似性为56.3 - 97.6%），但有一些例外。因此，本研究提供了有关东亚嗜吞噬细胞无形体分子特征以及p44/msp2全球多样性的重要信息。
