Unusual properties of a new division mutant of Escherichia coli.

The properties of a division mutant of Escherichia coli were investigated. At 42 degrees C, this mutant forms nonseptate, multinucleate, filamentous cells typical of division mutants, and at the permissive temperature, is sensitive to ultraviolet (UV) irradiation. Temperature and UV sensitivities are probably due to a single mutation. The mutant phenotype is dominant to wild type. The mutant cells make DNA nearly as effectively as control cells at 42 degrees C or following UV irradiation. They exhibit normal host-cell reactivation capacities and can express all manifestations of the SOS response with the exception of Weigle reactivation. The genetic lesion which mediates this pleiotropic effect is located very close to the leu locus of the linkage map.