Polyamine as a Signaling Molecule for Controlling an Adaptive Mutation

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Il Lae Jung and In Gyu Kim^*

Department of Radiation Biology, Environmental Radiation Research Center, Korean Atomic Energy Research Institute, P. O. Box 105, Yusong, Daejeon 305-600, Korea; fax: +82-42-861-9560; E-mail: igkim@kaeri.re.kr

^* To whom correspondence should be addressed.

Received January 17, 2008; Revision received March 13, 2008

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In the absence of exogenous polyamines, the polyamine-deficient Escherichia coli mutant shows not only a characteristic dual-phase growth with abnormal growth, growth arrest, and normal growth after mutation, but also a higher expression of the SOS genes than the polyamine-proficient wild type. The interval of the growth arrest is inversely regulated in a polyamine concentration-dependent manner. These results indicate that the polyamines can act as a signal not only for provoking an adaptive mutation, but also for hastening generation of an adaptive mutation.

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KEY WORDS: adaptive mutation, Escherichia coli, mutational speed, polyamine, SOS response

DOI: 10.1134/S0006297908110096

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