Role of the colicin A lysis protein in the expression of the colicin A operon.
The involvement of the cal gene, which encodes the colicin A lysis protein, in the expression of the colicin A operon is demonstrated. Colicin A synthesis by Escherichia coli was studied at various temperatures in cells containing either the wild-type colicin A operon or the colicin A operon with the cal gene deleted. The amount of colicin A produced was lower in cells containing the colicin A operon devoid of the cal gene than in wild-type cells. In cells treated with the antibiotic globomycin, the synthesis of colicin A was blocked in null cal mutants at all temperatures. It was blocked only at low temperature in cells containing the wild-type colicin A operon, but not in cells subjected to heat shock or azide treatment. The cal gene product may be an activator of colicin A expression and of its own expression. An unidentified product, possibly a heat-shock protein, may also be involved and could complement the cal gene product in some situations.
Cavard
Danièle
D
Laboratoire d'Ingénierie des Systémes Macromoléculaires, CNRS, 31 chemin Joseph Aiguier, BP 71, 13402 Marseille Cedex 20, France.
D001426:Bacterial Proteins / Q000235:genetics*; D003087:Colicins / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008074:Lipoproteins; D009876:Operon / Q000235:genetics
D001426:Bacterial Proteins; C058485:CAL protein, Citrobacter freundii; D003087:Colicins; D008074:Lipoproteins