Overexpression of the hslVU operon suppresses SOS-mediated inhibition of cell division in Escherichia coli.
A multicopy clone was isolated which conferred resistance to the SOS inducer nitrofurantoin in an Escherichia coli lon mutant. Plasmid pHL1 was found to contain a 7-8 kbp HindIII DNA insert from a region of the chromosome at 88.5 minutes. Further characterisation of pHL1 revealed that resistance to nitrofurantoin was due to the overexpression of the hslV-hslU operon which encodes an ATP-dependent protease complex in E. coli. The overexpression of hslVU also conferred resistance to ultraviolet irradiation in the lon mutant. It is proposed that when overproduced, the HslV-HslU protease complex can degrade SulA which is an endogenous inhibitor of the essential cell division protein FtsZ. The ability of HslVU to degrade SulA in vivo suggests that Lon and HslVU may share a range of substrates. Furthermore, the suppression of lon could be used as a simple genetic test of proteolytic activity of cloned HslVU.
Khattar
M M
MM
Institute of Cell and Molecular Biology, University of Edinburgh, UK. medhat@holyrood.ed.ac.uk
D049069:ATP-Dependent Proteases; D000251:Adenosine Triphosphatases / Q000096:biosynthesis* / Q000235:genetics; D001426:Bacterial Proteins / Q000378:metabolism; D002455:Cell Division; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins; D017931:DNA Primers; D010450:Endopeptidases / Q000096:biosynthesis* / Q000235:genetics; D004926:Escherichia coli / Q000166:cytology / Q000201:enzymology* / Q000235:genetics*; D029968:Escherichia coli Proteins; D005784:Gene Amplification; D006360:Heat-Shock Proteins / Q000096:biosynthesis; D009582:Nitrofurantoin / Q000494:pharmacology; D009876:Operon; D010957:Plasmids; D049070:Protease La; D011994:Recombinant Proteins / Q000096:biosynthesis; D013014:SOS Response, Genetics / Q000187:drug effects; D012697:Serine Endopeptidases; D013379:Substrate Specificity
D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D017931:DNA Primers; D029968:Escherichia coli Proteins; C071525:FtsZ protein, Bacteria; D006360:Heat-Shock Proteins; D011994:Recombinant Proteins; C053139:sulA protein, E coli; D009582:Nitrofurantoin; D010450:Endopeptidases; D049069:ATP-Dependent Proteases; D012697:Serine Endopeptidases; C483567:Lon protein, E coli; D049070:Protease La; D000251:Adenosine Triphosphatases