Ultraviolet sensitivity ofBacillus subtilis citD mutants

Cells ofBacillus subtilis 168 with deletions in thecitD locus were found to be sensitive to irradiation with ultraviolet light and to mitomycin C but were able to repair DNA damage induced by methyl methanesulfonate. The recombination abilities of these cells, as determined by transformation and PBS1-mediated transduction experiments, were unaffected by the deletion. These phenotypic characteristics do not result from a metabolic imbalance caused by the deficiency of a functional α-ketoglutarate dehydrogenase complex, but most likely are a consequence of a genetic locus involved in ultraviolet repair, which is deleted together with thecitK gene when the deletion is formed.