biostudies-literatureUnknown7Toyomane KThe anthrax toxin is a virulence factor produced by the bacterium <i>Bacillus anthracis</i>. Transcription of anthrax toxin genes is controlled by the transcription factor AtxA. Thus, AtxA is thought to be a key factor for the pathogenicity of <i>B. anthracis</i>. Despite its important role in <i>B. anthracis</i> infection, the molecular mechanism by which AtxA controls expression of anthrax toxin remains unclear. This study aimed to characterize the molecular mechanism of AtxA-mediated regulation of protective antigen (PA), a component of anthrax toxin encoded by the <i>pagA</i> gene. First, the interaction between the upstream region of <i>pagA</i> and AtxA was evaluated in vivo by constructing a transcriptional fusion of the upstream region with an auxotrophic marker. The results showed that (i) the upstream region of <i>pagA</i> suppressed transcription of the downstream gene and (ii) AtxA recovered suppressed transcription. Second, in vitro analysis using a gel mobility shift assay was performed to evaluate binding specificity of the AtxA-DNA interaction. The result showed sequence-independent binding of AtxA to DNA. Taken together, our findings suggest that the expression of PA was suppressed by the upstream region of <i>pagA</i> and that an interaction of AtxA and the upstream region releases the suppression.PeerJe6718https://www.ebi.ac.uk/biostudies/studies/S-EPMC6463858biostudies-literatureUpstream sequence-dependent suppression and AtxA-dependent activation of protective antigens in <i>Bacillus anthracis</i>.PMC6463858Furuta YToyomane KHigashi HFujikura DfalseUpstream sequence-dependent suppression and AtxA-dependent activation of protective antigens in <i>Bacillus anthracis</i>.The anthrax toxin is a virulence factor produced by the bacterium <i>Bacillus anthracis</i>. Transcription of anthrax toxin genes is controlled by the transcription factor AtxA. Thus, AtxA is thought to be a key factor for the pathogenicity of <i>B. anthracis</i>. Despite its important role in <i>B. anthracis</i> infection, the molecular mechanism by which AtxA controls expression of anthrax toxin remains unclear. This study aimed to characterize the molecular mechanism of AtxA-mediated regulation of protective antigen (PA), a component of anthrax toxin encoded by the <i>pagA</i> gene. First, the interaction between the upstream region of <i>pagA</i> and AtxA was evaluated in vivo by constructing a transcriptional fusion of the upstream region with an auxotrophic marker. The results showed that (i) the upstream region of <i>pagA</i> suppressed transcription of the downstream gene and (ii) AtxA recovered suppressed transcription. Second, in vitro analysis using a gel mobility shift assay was performed to evaluate binding specificity of the AtxA-DNA interaction. The result showed sequence-independent binding of AtxA to DNA. Taken together, our findings suggest that the expression of PA was suppressed by the upstream region of <i>pagA</i> and that an interaction of AtxA and the upstream region releases the suppression.2019-01-01T00:00:00Z20192024-11-15T11:09:11.311Z2019-06-06T21:11:04ZS-EPMC64638583099729110.7717/peerj.6718