Regulatory processes and the origins of spontaneous mutations.

A review of information currently available about the origins of spontaneous mutational events suggests that there may be a role for known cellular control mechanisms in determining the frequencies with which such events can occur. Attention is also directed to recent findings with antimutator (dnaE) mutants of Escherichia coli which indicate that the final step involved in generating a spontaneous mutational event may be different from that involved in generating an SOS-dependent mutational event. Finally, the possible involvement of various sorts of treatments collectively referred to as stress responses (heat shock, cold shock or oxidative damage, etc.) in generating random mutations is discussed; if there is such an involvement, this may represent one way in which organisms are programmed to adapt to a wide variety of environmental challenges.