Indications of an involvement of heat-shock proteins in restoration of repression of temperative-inducible lambda prophage.

Characteristics of lambda c/ts857 prophages that can be attributed to the ability of the temperature-sensitive phage repressor to renature at low temperature are not apparent in host cells that contain a mutation in the htpR gene. Host killing by prophages that are N- or are blocked in DNA synthesis is not prevented by the return of mutant cells to low temperature, and recovery of cells in which the phage remains derepressed is not delayed if the prophage is a mutant that cannot kill. These and other findings suggest that the phage repressor protein is unusually susceptible to inactivation in cells that are unable to respond to heat shock.