JB
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Bashyam, M. D.
Right arrow Articles by Tyagi, A. K.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Bashyam, M. D.
Right arrow Articles by Tyagi, A. K.

J. Bacteriol., 08 1996, 4847-4853, Vol 178, No. 16
Copyright © 1996, American Society for Microbiology

A study of mycobacterial transcriptional apparatus: identification of novel features in promoter elements

MD Bashyam, D Kaushal, SK Dasgupta and AK Tyagi
Department of Biochemistry, University of Delhi South Campus, India.

Our earlier studies on transcriptional signals of mycobacteria had revealed that (i) strong promoters occur less frequently in the slowly growing pathogen Mycobacterium tuberculosis H37Rv than in the fast- growing saprophyte M. smegmatis and (ii) mycobacterial promoters function poorly in Escherichia coli. We now present evidence that RNA polymerases of M. smegmatis, M. tuberculosis, and M. bovis BCG recognize promoter elements with comparable efficiencies. Analysis of these randomly isolated mycobacterial promoters by DNA sequencing, primer extension, and deletion experiments revealed that their -10 regions are highly similar to those of E. coli promoters, in contrast to their -35 regions, which can tolerate a greater variety of sequences, owing presumably to the presence of multiple sigma factors with different or overlapping specificities for -35 regions, as reported earlier for the Streptomyces promoters. A comparison of the - 10 and -35 binding domains of MysA, HrdB, and RpoD (the principal sigma factors of M. smegmatis, Streptomyces aureofaciens, and E. coli, respectively) showed that all three sigma factors have nearly identical -10 binding domains. However, the -35 binding domains of the principal mycobacterial and streptomycete sigma factors, although nearly identical to each other, are vastly different from the corresponding region of the sigma factor of E. coli. Thus, the transcriptional signals of mycobacteria have features in common with Streptomyces promoters but differ from those of E. coli because of major differences in the -35 regions of the promoters and the corresponding binding domain in the sigma factor.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Appl. Environ. Microbiol. Infect. Immun. Eukaryot. Cell
Mol. Cell. Biol. J. Virol. Microbiol. Mol. Biol. Rev.
ALL ASM JOURNALS

Copyright © 1996 by the American Society for Microbiology. All rights reserved.