VirS, an OmpR/PhoB subfamily response regulator, is required for activation of vapA gene expression in Rhodococcus equi

BMC Microbiology

Shinji Takai¹  Shiko Miyazaki¹  Hirofumi Hagiuda¹  Tatsuya Takeuchi¹  Takuya Hirota¹  Tsutomu Kakuda¹ 

[1] Laboratory of Animal Hygiene, School of Veterinary Medicine, Kitasato University, Higashi 23-35-1, Towada 034-8628, Aomori, Japan

关键词: VirS;    Rhodococcus equi VapA protein virulence;    Rhodococcus equi;    Opportunistic infections;   

Others  :  1137757
DOI  :  10.1186/s12866-014-0243-1

 received in 2014-05-15, accepted in 2014-09-09,  发布年份 2014

【 摘 要 】

Background

Rhodococcus equi is an important pulmonary pathogen in foals and in immunocompromised individuals. Virulent R. equi strains carry an 80-90 kb virulence plasmid that expresses the virulence-associated protein A (VapA). VapA expression is regulated by temperature and pH. The LysR-type transcriptional regulator, VirR, is involved in the regulation of the vapA gene. To examine the mechanism underlying transcriptional regulation of vapA, we characterized an R. equi mutant in which another putative transcriptional regulator encoded on the virulence plasmid, VirS, was deleted.

Results

Deletion of virS reduced vapA promoter activity to non-inducible levels. Complementary expression of VirS in the virS deletion mutant restored transcription at the P_vapA promoter, even under non-inducing conditions (30°C and pH 8.0). In addition, VirS expression increased P_vapA promoter activity in the absence of functional VirR. Further, transcription of the icgA operon containing virS was regulated by pH and temperature in the same manner as vapA.

Conclusions

This study suggests that VirS is required for VapA expression and that regulation of P_vapA-promoter activity may be achieved by controlling VirS expression levels.

【 授权许可】

   
2014 Kakuda et al.; licensee BioMed Central Ltd.

【 图 表 】

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