Analysis of Salmonella pathogenicity island (SPI) 2 gene expression = Salmonella의 병원성 유전자 발현 연구

다국어 초록 (Multilingual Abstract)

Salmonella pathogenicity island 2 (SPI2) encodes a putative type Ⅲ secretion system necessary for replication inside macrophages systemic infection in animals. The genes for the secretion system such as ssaH are transcribed preferentially after Salmonella enters host cells. The transcriptional organization of 3 genes of SPI2 was investigated, which encode components of one of two type Ⅲ secretion apparatus of Salmonella typhimurium. ssaH, I, J constitute one operon of 1.5 kb and the promoter of this operon lies upstream of ssaH. The transcriptional regulation of ssaH (operon) was studied by primer extension analysis. It was found that stationary growth phase-specific transcription of ssaH is most efficient in the presence of OmpR (pleiotropic regulator of Salmonella virulence genes), InvF, SsrB (local regulator of SPI1 and 2), IHF, and Fis (nucleoid associated proteins). Furthermore, we constructed two kinds of reporter plasmid to know whether the ssaH expression is specific to Salmonella. In this study, it was found that SsrB was prerequisite of ssaH expression because a ssaH was not expressed in E. coli which is absent of SPI.