[ODP18] 4. Genetics / Genomics / Biotechnology -c. Gene regulation and transcriptome analysis

[ODP-085] Regulation of expression of the VarS/VarA-controlled sRNA by ArcA in Vibrio alginolyticus

Takehiko Mima¹, Eka Darwinata Agus², Kazuyoshi Gotoh³, Yumiko Yamamoto³, Osamu Matsushita³ (¹Dept. Med. Technol., Fac. Health Sci., Ehime Pref. Univ. Health Sci., ²Dept. Clin. Microbiol., Fac. Med., Udayana Univ., Indonesia, ³Dept. Bacteriol., Okayama Univ. Grad. Sch. Med. Dent. Pharm. Sci.)

VarS/VarA two-component regulatory system controls the expression of target genes via regulating the transcription of multiple small RNAs (sRNAs). Vibrio alginolyticus possesses four sRNAs (sRNA1, 2, 3, and 4) whose expressions are regulated by VarS/VarA system. Our previous studies suggested that the expression of sRNAs is controlled by regulators other than VarS/VarA system. Using the pull-down technique, several proteins that specifically bound to each sRNA promoter were identified. ArcA, a response regulator of ArcA/ArcB system that mediates adaptation to anaerobic growth conditions, was pulled down when sRNA1 promoter was used as bait. Electromobility shift assay with recombinant ArcA confirmed that ArcA bound to the predicted ArcA binding sequence on the sRNA1 promoter region, but not to other sRNA promoters. Both transcriptional activity and amount of sRNA1 were decreased in the arcA deletion mutant when cells were grown under anaerobic condition. But neither was changed under aerobic condition. These results demonstrate that expression of sRNA1 is regulated by ArcA. It seems likely that expression of VarS/VarA-controlled sRNAs is controlled by multiple environmental signals.