Sigma factor F does not prevent rifampin inhibition of RNA polymerase or cause rifampin tolerance in Mycobacterium tuberculosis.
J Bacteriol
; 192(20): 5472-9, 2010 Oct.
Article
in En
| MEDLINE
| ID: mdl-20729364
ABSTRACT
The tolerance of Mycobacterium tuberculosis to antituberculosis drugs is a major reason for the lengthy therapy needed to treat a tuberculosis infection. Rifampin is a potent inhibitor of RNA polymerase (RNAP) in vivo but has been shown to be less effective against stationary-phase bacteria. Sigma factor F is associated with bacteria entering stationary phase and has been proposed to impact rifampin activity. Here we investigate whether RNAP containing SigF is more resistant to rifampin inhibition in vitro and whether overexpression of sigF renders M. tuberculosis more tolerant to rifampin. Real-time and radiometric in vitro transcription assays revealed that rifampin equally inhibits transcription by RNAP containing sigma factors SigA and SigF, therefore ruling out the hypothesis that SigF may be responsible for increased resistance of the enzyme to rifampin in vitro. In addition, overexpression or deletion of sigF did not alter rifampin susceptibility in axenic cultures of M. tuberculosis, indicating that SigF does not affect rifampin tolerance in vivo.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Rifampin
/
Sigma Factor
/
Bacterial Proteins
/
DNA-Directed RNA Polymerases
/
Drug Resistance, Bacterial
/
Anti-Bacterial Agents
/
Mycobacterium tuberculosis
Language:
En
Journal:
J Bacteriol
Year:
2010
Document type:
Article
Affiliation country:
Switzerland