Global regulatory function of the low oxygen-induced transcriptional regulator LoiA in Salmonella Typhimurium revealed by RNA sequencing

摘要

Salmonella entericaserovar Typhimurium (S.Typhimurium) is a major intestinal pathogen that can infect both humans and a variety of animals. LoiA, a novel virulence-regulating protein encoded inSalmonellapathogenicity island (SPI)-14, has been shown to be induced under low oxygen conditions and contribute toS.Typhimurium invasion into intestinal epithetical cells by activating the SPI-1 invasion genes. However, the global regulatory network of LoiA remains unknown. Here, we used high-throughput RNA sequencing (RNA-seq) technology to investigate the regulatory function of LoiA inS.Typhimurium under low oxygen conditions. A total of 1250 genes were differentially expressed between theloiAmutant and the wild-type strain; 413 genes were up-regulated and 837 were down-regulated. SPI-1 gene expression was down-regulated in theloiAmutant, consistent with previous results. SPI-2 gene expression was not affected by deletion ofloiA; the expression of most genes involved in flagellar basal body and hook biosynthesis was up-regulated in theloiAmutant, while the expression of genes associated with flagellin, motility, and chemotaxis was down-regulated; the expression oflon, encoding an ATP-dependent protease, was up-regulated in the mutant. This study indicates that LoiA regulates a variety of virulence-associated genes inS.Typhimurium. The negative regulation of Lon protease by LoiA indicates that LoiA can regulates several virulence-associated genes inS.Typhimurium via the Lon protease.