Mycobacterium tuberculosis ftsZ expression and minimal promoter activity.
Optimal levels of ftsZ gene product are shown to be required for initiation of the cell division process in Mycobacterium tuberculosis. Here, we report that the ftsZ gene expression is sharply down-regulated during starvation and hypoxia, conditions that are believed to result in growth arrest, but is restored upon dilution of cultures into fresh oxygen-rich media. Primer extension analysis identified four transcriptional start sites, designated as P1, P2, P3 and P4 at nucleotide positions -43, -101, -263, and -787, respectively, in the immediate upstream flanking region of the ftsZ initiation codon. Promoter deletion and homologous recombination experiments revealed that ftsZ expression from the 101-bp region is sufficient for M. tuberculosis viability. All promoter strains had reduced FtsZ levels compared to wild-type, although the loss of P4 severely compromised FtsZ levels during both the active and stationary phases. We propose that ftsZ expression from all promoters is required for optimal intracellular FtsZ levels and that the activities of P4 and possibly other promoters are down-regulated during growth-arrest conditions.
Kiran
Manjot
M
Biochemistry Department, The University of Texas Health Science Center @ Tyler, Tyler, TX 75708, USA.
Maloney
Erin
E
Lofton
Hava
H
Chauhan
Ashwini
A
Jensen
Rasmus
R
Dziedzic
Renata
R
Madiraju
Murty
M
Rajagopalan
Malini
M
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D002455:Cell Division; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D006801:Humans; D055985:Latent Tuberculosis / Q000378:metabolism; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction
D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D004269:DNA, Bacterial; C071525:FtsZ protein, Bacteria