Abstract
The cytokinetic protein FtsZ plays a pivotal role in regulation of cell division in bacteria. Multiple promoters regulate transcription of the
ftsZ gene in
Escherichia coli, Streptomyces and
Bacillus species. In order to identify promoter activity-containing regions of the
ftsZ gene of
Mycobacterium tuberculosis H37Rv (Mt
ftsZ) in vivo, different regions upstream of Mt
ftsZ, namely, the
ftsQ–ftsZ intergenic region, the
ftsQ open reading frame (ORF), and different regions of
ftsQ ORF, were analyzed in a
gfp reporter plasmid in
Mycobacterium smegmatis mc
2155 cells. Flow cytometric analysis of mid-logarithmic
M. smegmatis mc
2155 cells containing these transcription fusion constructs revealed GFP expression in the cells harboring the
ftsQ–ftsZ intergenic region (172 bp), the entire
ftsQ ORF (945 bp), and 5′ 467-bp and 3′ 217-bp regions of
ftsQ ORF. RT-PCR analyses on RNA from
M. smegmatis mc
2155 cells, transformed with the entire
ftsQ ORF-
ftsQ–ftsZ intergenic region-containing construct, as well as on RNA from
M. tuberculosis, confirmed that the regions identified indeed elicit promoter activity. Semi-quantitative RT-PCR analyses of
gfp transcripts driven by cloned Mt
ftsZ promoter regions in
M. smegmatis cells showed threefold higher promoter activity from
ftsQ ORF than from the
ftsQ–ftsZ intergenic region. Expression from the individual 5′ and 3′ regions of
ftsQ ORF was almost equivalent to that from the
ftsQ–ftsZ intergenic region. RT-PCR analyses on RNA from
M. tuberculosis quantitatively confirmed these promoter activities. Thus, at least three independent regions in the immediate upstream sequence of Mt
ftsZ contain promoter activity, with the major contribution coming from
ftsQ ORF.