RT Journal Article
T1 rstB regulates expression of the photobacterium damselae subsp damselae major virulence factors damselysin, phobalysin P and phobalysin C
A1 Terceti, Mateus de Souza
A1 Rivas Fontenla, Amable José
A1 Álvarez, Laura
A1 Noia Guldrís, Manuel
A1 Cava, Felipe
A1 Rodríguez Osorio, Carlos
K1 RstAB
K1 Hemolysin
K1 Photobacterium damselae
K1 Damselysin
K1 Phobalysin
K1 Vibriosis
K1 CarSR
AB The marine pathogenic bacterium Photobacterium damselae subsp. damselae causessepticemia in marine animals and in humans. The pPHDD1 plasmid-encodedhemolysins damselysin (Dly) and phobalysin P (PhlyP), and the chromosome-encodedhemolysin phobalysin C (PhlyC) constitute its main virulence factors. However, themechanisms by which expression of these three hemolysins is regulated remainunknown. Here we report the isolation of a mini-Tn10 transposon mutant which showeda strong impairment in its hemolytic activity. The transposon disrupted a putativesensor histidine kinase gene vda_000600 (rstB), which together with vda_000601 (rstA)is predicted to encode a putative two-component regulatory system. This systemshowed to be homologous to the Vibrio cholerae CarSR/VprAB and Escherichia coliRstAB systems. Reconstruction of the mutant by allelic exchange of rstB showedequal impairment in hemolysis, and complementation with a plasmid expressing rstABrestored hemolysis to wild-type levels. Remarkably, we demonstrated by promoterexpression analyses that the reduced hemolysis in the rstB mutant was accompaniedby a strong decrease in transcription activities of the three hemolysin genes dly(damselysin), hlyApl (phobalysin P) and hlyAch (phobalysin C). Thus, RstB, encoded inthe small chromosome, regulates plasmid and chromosomal virulence genes. We alsofound that reduced expression of the three virulence genes correlated with a strongdecrease in virulence in a sea bass model, demonstrating that RstB constitutes a masterregulator of the three P. damselae subsp. damselae hemolysins and plays critical rolesin the pathogenicity of this bacterium. This study represents the first evidence of a directrole of a RstAB-like system in the regulation of bacterial toxins
PB Frontiers Media
YR 2017
FD 2017
LK http://hdl.handle.net/10347/22634
UL http://hdl.handle.net/10347/22634
LA eng
NO Terceti MS, Rivas AJ, Alvarez L, Noia M, Cava F and Osorio CR (2017) rstB Regulates Expression of the Photobacterium damselae subsp. damselae Major Virulence Factors Damselysin, Phobalysin P and Phobalysin C. Front. Microbiol. 8:582. doi: 10.3389/fmicb.2017.00582
DS Minerva
RD 27 abr 2026