The Global Regulator ArcA Modulates Expression of Virulence Factors in Vibrio cholerae

AUTOR(ES)

Sengupta, Nilanjan

FONTE

American Society for Microbiology

RESUMO

A Vibrio cholerae arcA mutant was constructed and used to examine the role of the global anaerobiosis response regulator ArcA in the expression of virulence factors in this important human pathogen. In V. cholerae, expression of the major virulence factors cholera toxin (CT) and toxin-coregulated pilus (TCP) is regulated by the transcriptional activator ToxT. toxT expression, in turn, is controlled by the transmembrane DNA binding proteins ToxR and TcpP. In the V. cholerae arcA mutant, although ToxR and TcpP were unaffected, Northern blot and reverse transcription-PCR analyses indicated that the expression of toxT was significantly decreased with concomitant reduction in the expression of CT and TCP. CT and TCP expression was completely restored in the V. cholerae arcA mutant strain by expressing a cloned toxT gene in the mutant. These results suggest that ArcA functions as a positive regulator of toxT expression under both aerobic and anaerobic conditions, although as expected, the effect was more pronounced during anaerobic growth. This was reflected in a reduction of virulence of the V. cholerae arcA mutant strain in the infant mouse cholera model.

Documentos Relacionados

• The Global Regulator ArcA Controls Resistance to Reactive Nitrogen and Oxygen Intermediates in Salmonella enterica Serovar Enteritidis
• TcpP protein is a positive regulator of virulence gene expression in Vibrio cholerae
• Effect of Anaerobiosis on Expression of Virulence Factors in Vibrio cholerae
• Bacterial defense against aging: role of the Escherichia coli ArcA regulator in gene expression, readjusted energy flux and survival during stasis.
• arcA (dye), a global regulatory gene in Escherichia coli mediating repression of enzymes in aerobic pathways.