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首页> 外文期刊>Infection and immunity >Characterization and Transcriptional Analysis of Gene Clusters for a Type IV Secretion Machinery in Human Granulocytic and Monocytic Ehrlichiosis Agents
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Characterization and Transcriptional Analysis of Gene Clusters for a Type IV Secretion Machinery in Human Granulocytic and Monocytic Ehrlichiosis Agents

机译：人类粒细胞和单核细胞埃希氏病病原体中IV型分泌机制的基因簇的表征和转录​​分析。

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Anaplasma (Ehrlichia) phagocytophila and Ehrlichia chaffeensis, the etiologic agents of granulocytic and monocytic ehrlichioses, respectively, are obligatory intracellular bacteria that cause febrile systemic illness in humans. We identified and characterized clusters of genes for a type IV secretion machinery in these two bacteria, and analyzed their gene expression in cell culture and mammalian hosts. Eight virB and virD genes were found in each bacterial genome, and all of the genes were transcribed in cell culture. Although the gene order and orientation were similar to those found in other bacteria, the eight virB and virD genes were clustered at two separate loci in each genome. Five of the genes (virB8, virB9, virB10, virB11, and virD4) were located downstream from a ribA gene. These five genes in both A. phagocytophila and E. chaffeensis were polycistronically transcribed and controlled through at least two tandem promoters located upstream of the virB8 gene in human leukemia cell lines. The virB9 gene of A. phagocytophila was transcriptionally active in peripheral blood leukocytes from human ehrlichiosis patients and experimentally infected animals. Three of the remaining genes (virB3, virB4, and virB6) of both A. phagocytophila and E. chaffeensis were arranged downstream from a sodB gene and cotranscribed with the sodB gene through one or more sodB promoters in human leukocytes. This suggests that transcription of the three virB genes in these two Anaplasma and Ehrlichia spp. is regulated by factors that influence the sodB gene expression. This unique regulation of gene expression for the type IV secretion system may be associated with intracellular survival and replication of Anaplasma and Ehrlichia spp. in granulocytes or monocytes.
机译：粒细胞性和单核细胞性埃希氏菌病的病原体分别是浆质（埃里希氏）吞噬细胞和 chaffeensis 导致人类发热性全身疾病的细胞内细菌。我们鉴定和表征了这两种细菌中IV型分泌机制的基因簇，并分析了它们在细胞培养和哺乳动物宿主中的基因表达。在每个细菌基因组中发现了8个 virB 和 virD 基因，所有基因都在细胞培养物中转录。尽管基因顺序和方向与其他细菌中的相似，但八个 virB 和 virD 基因聚集在每个基因组的两个单独的基因座上。五个基因（ virB8 ， virB9 ， virB10 ， virB11 和 virD4 ）位于 ribA 基因的下游。这两个基因都在 A中。吞噬细胞和 E。 Chaffeensis 是多顺反子转录的，并通过至少两个位于人白血病细胞系 virB8 基因上游的串联启动子控制。 A的 virB9 基因。在人类埃希氏病患者和实验感染动物的外周血白细胞中，吞噬细胞具有转录活性。两个 A的其余三个基因（ virB3 ， virB4 和 virB6 ）。吞噬细胞和 E。 Chaffeensis 排列在 sodB 基因的下游，并通过人类白细胞中的一个或多个 sodB 启动子与 sodB 基因共转录。这表明在这两个浆和 Ehrlichia spp中的三个 virB 基因的转录。受影响 sodB 基因表达的因素调控。 IV型分泌系统基因表达的这种独特调节可能与浆膜和埃里希氏菌 spp的细胞内存活和复制有关。在粒细胞或单核细胞中。

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