[Physical mapping of Streptomyces coelicolor A3(2) actinophage DNA. I. Location of the c-region of actinophage phiC31].

Mutants of temperate actinophage phi C31 Streptomyces coelicolor A3(2) having an increased resistance to chelating agents (sodium EDTA and sodium citrate) were isolated. Most of these mutants were not able to lysogenize sensitive cultures (c-mutants). DNA molecules of four c-mutants resistant to chelating agents were shown to be deleted by electron microscopy of DNA heteroduplexes. The four deletions were located in the central region of phi C31 DNA molecule. The deleted segment of 1000 base pairs common for molecules of all c-mutants is located in a region 47,2--49,9% and indicates the position of c-region on the physical map of phi C31 actinophage. The size of the region containing delections of all analyzed c-mutants is 1700 base pairs. The c-region on the heteroduplex map was oriented in relation to the known genetic map of phi C31.