Fernandes ND, Husson RN; American Society for Microbiology. General Meeting.
Abstr Gen Meet Am Soc Microbiol. 1999 May 30-Jun 3; 99: 648 (abstract no. U-76).
Childrens Hospital Harvard Medical School, Boston, MA.
The bacterial determinants of pathogenicity of M. tuberculosis are largely unknown. This study attempts to improve our understanding of the pathogenesis of tuberculosis by providing a clearer picture of the molecular biology of mycobacterial gene expression. Alternative sigma factors whose activity is essential under conditions relevant to in vivo replication and survival in a hostile environment, can provide a means to identify regulated genes that are essential for mycobacterial virulence. As a first step towards achieving this goal, as well as to understand the nature of alternative sigma factor control of mycobacterial gene expression at the molecular level, we attempted to identify genes under the control of two alternative sigma factors, Sig H and Sig E. In order to be able to identify genes under the control of Sig E, we utilized a molecular genetic approach by screening a M. tuberculosis genomic DNA library constructed in a promoter- probe vector pCV77 for promoters that were active in the wild type M. smegmatis but inactive in a Sig E mutant strain. We have identified five genes under the control of Sig E and their promoters have been defined by using primer extension analyses. We determined that Sig H is autoregulated in M. smegmatis. Sig H promoters in M. tuberculosis and M. smegmatis were found by primer extension analyses to have highly similar -35 regions that corresponded to the extracytoplasmic function sigma factor consensus. We therefore undertook a computational approach utilizing this consensus sequence and GCG software to screen the M. tuberculosis genome sequence. This screen resulted in the initial identification of five genes with the consensus sequence present upstream of the coding sequence. The availability of this data enhances our ability to elucidate the role(s) of these sigma factors in the regulation of M. tuberculosis gene expression.
Publication Types:
Keywords:
- Base Sequence
- Consensus Sequence
- Mycobacterium
- Mycobacterium tuberculosis
- Promoter Regions (Genetics)
- Sigma Factor
- Tuberculosis
- Virulence
- genetics
Other ID:
UI: 102195817
From Meeting Abstracts