Physiological consequences associated with overproduction of Mycobacterium tuberculosis FtsZ in mycobacterial hosts

Microbiology. 2002 Apr;148(Pt 4):961-971. doi: 10.1099/00221287-148-4-961.


The ftsZ gene of Mycobacterium tuberculosis H37Rv has been characterized as the first step in determining the molecular events involved in the cell division process in mycobacteria. Western analysis revealed that intracellular levels of FtsZ are growth phase dependent in both M. tuberculosis and Mycobacterium smegmatis. Unregulated expression of M. tuberculosis ftsZ from constitutive hsp60 and dnaA promoters in M. tuberculosis hosts resulted in lethality whereas expression from only the hsp60 promoter was toxic in M. smegmatis hosts. Expression of ftsZ from the dnaA promoter in M. smegmatis resulted in approximately sixfold overproduction and the merodiploids exhibited slow growth, an increased tendency to clump and filament, and in some cases produced buds and branches. Many of the cells also contained abnormal and multiple septa. Expression of ftsZ from the chemically inducible acetamidase promoter in M. smegmatis hosts resulted in approximately 22-fold overproduction of FtsZ and produced filamentous cells, many of which lacked any visible septa. Visualization of the M. tuberculosis FtsZ tagged with green fluorescent protein in M. smegmatis by fluorescence microscopy revealed multiple fluorescent FtsZ foci, suggesting that steps subsequent to the formation of organized FtsZ structures but prior to septum formation are blocked in FtsZ-overproducing cells. Together these results suggest that the intracellular concentration of FtsZ protein is critical for productive septum formation in mycobacteria.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Bacterial Proteins / genetics*
  • Cell Division
  • Cloning, Molecular
  • Cytoskeletal Proteins*
  • DNA Primers
  • Diploidy
  • GTP Phosphohydrolases / genetics
  • Gene Expression Regulation, Bacterial
  • Gene Expression Regulation, Enzymologic
  • Mycobacterium smegmatis / enzymology
  • Mycobacterium smegmatis / ultrastructure
  • Mycobacterium tuberculosis / enzymology
  • Mycobacterium tuberculosis / genetics
  • Mycobacterium tuberculosis / physiology*
  • Polymerase Chain Reaction
  • Recombinant Proteins / metabolism
  • Species Specificity
  • Transformation, Genetic


  • Bacterial Proteins
  • Cytoskeletal Proteins
  • DNA Primers
  • FtsZ protein, Bacteria
  • Recombinant Proteins
  • GTP Phosphohydrolases