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Insights into the function of the WhiB-like protein of mycobacteriophage TM4--a transcriptional inhibitor of WhiB2.
- Source :
-
Molecular microbiology [Mol Microbiol] 2010 Aug; Vol. 77 (3), pp. 642-57. Date of Electronic Publication: 2010 Jun 09. - Publication Year :
- 2010
-
Abstract
- WhiB-like proteins of actinomycetes are known to co-ordinate iron-sulfur (Fe-S) clusters and are believed to have regulatory functions in many essential bacterial processes. The systematic determination of the genome sequences of mycobacteriophages has revealed the presence of several whiB-like genes in these viruses. Here we focussed on the WhiB-like protein of mycobacteriophage TM4, WhiBTM4. We provide evidence that this viral protein is capable of co-ordinating a Fe-S cluster. The UV-visible absorption spectra obtained from freshly purified and reconstituted WhiBTM4 were consistent with the presence of an oxygen sensitive [2Fe-2S] cluster. Expression of WhiBTM4 in the mycobacterial host led to hindered septation resembling a WhiB2 knockout phenotype whereas basal expression of WhiBTM4 led to superinfection exclusion. The quantification of mRNA-levels during phage infection showed that whiBTM4 is a highly transcribed early phage gene and a dominant negative regulator of WhiB2. Strikingly, both apo-WhiB2 of Mycobacterium tuberculosis and apo-WhiBTM4 were capable of binding to the conserved promoter region upstream of the whiB2 gene indicating that WhiB2 regulates its own synthesis which is inhibited in the presence of WhiBTM4. Thus, we provide substantial evidence supporting the hypothesis of viral and bacterial WhiB proteins being important Fe-S containing transcriptional regulators with DNA-binding capability.
- Subjects :
- Amino Acid Motifs
Amino Acid Sequence
Bacterial Proteins chemistry
Bacterial Proteins metabolism
Gene Expression Regulation, Bacterial
Molecular Sequence Data
Mycobacteriophages chemistry
Mycobacteriophages genetics
Mycobacterium smegmatis genetics
Mycobacterium smegmatis metabolism
Mycobacterium smegmatis virology
Mycobacterium tuberculosis chemistry
Mycobacterium tuberculosis metabolism
Mycobacterium tuberculosis virology
Protein Binding
Sequence Alignment
Transcription Factors chemistry
Transcription Factors metabolism
Viral Proteins chemistry
Viral Proteins genetics
Bacterial Proteins genetics
Down-Regulation
Mycobacteriophages metabolism
Mycobacterium tuberculosis genetics
Transcription Factors genetics
Transcription, Genetic
Viral Proteins metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1365-2958
- Volume :
- 77
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Molecular microbiology
- Publication Type :
- Academic Journal
- Accession number :
- 20545868
- Full Text :
- https://doi.org/10.1111/j.1365-2958.2010.07235.x