Essential roles for imuA'- and imuB-encoded accessory factors in DnaE2-dependent mutagenesis in Mycobacterium tuberculosis.
Proc Natl Acad Sci U S A
; 107(29): 13093-8, 2010 Jul 20.
Article
em En
| MEDLINE
| ID: mdl-20615954
ABSTRACT
In Mycobacterium tuberculosis (Mtb), damage-induced mutagenesis is dependent on the C-family DNA polymerase, DnaE2. Included with dnaE2 in the Mtb SOS regulon is a putative operon comprising Rv3395c, which encodes a protein of unknown function restricted primarily to actinomycetes, and Rv3394c, which is predicted to encode a Y-family DNA polymerase. These genes were previously identified as components of an imuA-imuB-dnaE2-type mutagenic cassette widespread among bacterial genomes. Here, we confirm that Rv3395c (designated imuA') and Rv3394c (imuB) are individually essential for induced mutagenesis and damage tolerance. Yeast two-hybrid analyses indicate that ImuB interacts with both ImuA' and DnaE2, as well as with the beta-clamp. Moreover, disruption of the ImuB-beta clamp interaction significantly reduces induced mutagenesis and damage tolerance, phenocopying imuA', imuB, and dnaE2 gene deletion mutants. Despite retaining structural features characteristic of Y-family members, ImuB homologs lack conserved active-site amino acids required for polymerase activity. In contrast, replacement of DnaE2 catalytic residues reproduces the dnaE2 gene deletion phenotype, strongly implying a direct role for the alpha-subunit in mutagenic lesion bypass. These data implicate differential protein interactions in specialist polymerase function and identify the split imuA'-imuB/dnaE2 cassette as a compelling target for compounds designed to limit mutagenesis in a pathogen increasingly associated with drug resistance.
Texto completo:
1
Coleções:
01-internacional
Contexto em Saúde:
2_ODS3
/
3_ND
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
/
Mutagênese Insercional
/
DNA Polimerase Dirigida por DNA
/
Mycobacterium tuberculosis
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
2010
Tipo de documento:
Article