Rv3133c/dosR is a transcription factor that mediates the hypoxic response of Mycobacterium tuberculosis.
Unlike many pathogens that are overtly harmful to their hosts, Mycobacterium tuberculosis can persist for years within humans in a clinically latent state. Latency is often linked to hypoxic conditions within the host. Among M. tuberculosis genes induced by hypoxia is a putative transcription factor, Rv3133c/DosR. We performed targeted disruption of this locus followed by transcriptome analysis of wild-type and mutant bacilli. Nearly all the genes powerfully regulated by hypoxia require Rv3133c/DosR for their induction. Computer analysis identified a consensus motif, a variant of which is located upstream of nearly all M. tuberculosis genes rapidly induced by hypoxia. Further, Rv3133c/DosR binds to the two copies of this motif upstream of the hypoxic response gene alpha-crystallin. Mutations within the binding sites abolish both Rv3133c/DosR binding as well as hypoxic induction of a downstream reporter gene. Also, mutation experiments with Rv3133c/DosR confirmed sequence-based predictions that the C-terminus is responsible for DNA binding and that the aspartate at position 54 is essential for function. Together, these results demonstrate that Rv3133c/DosR is a transcription factor of the two-component response regulator class, and that it is the primary mediator of a hypoxic signal within M. tuberculosis.
Park
Heui-Dong
HD
Department of Pathobiology, University of Washington, Seattle, WA 98195, USA.
Guinn
Kristi M
KM
Harrell
Maria I
MI
Liao
Reiling
R
Voskuil
Martin I
MI
Tompa
Martin
M
Schoolnik
Gary K
GK
Sherman
David R
DR
D001224:Aspartic Acid / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D018390:Gene Targeting; D017930:Genes, Reporter; D006801:Humans; D000860:Hypoxia / Q000378:metabolism*; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D010100:Oxygen / Q000378:metabolism; D011485:Protein Binding; D012045:Regulatory Sequences, Nucleic Acid; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014376:Tuberculosis / Q000378:metabolism
D001426:Bacterial Proteins; D014157:Transcription Factors; D001224:Aspartic Acid; D010100:Oxygen