Formation of additional contacts of chromosome with membrane in the process of DNA repair synthesis in bacterial cells

An increase in the amount of membrane‐bound DNA was found in B. subtilis cells with UV‐induced DNA repair synthesis as compared to untreated cells. It was shown that DNA repair synthesis occurred in DNA membrane complexes (DMC) formed during UV‐irradiation. UV‐induced formation of DMC was observed in cells of wild type strains which were capable of repairing damaged DNA but not in a mutant defective in DNA‐polymerase I. It was demonstrated that DNA‐polymerase I is located on the membrane of B. subtilis cells. This suggested a participation of DNA‐polymerase I in binding of the chromosome to the membrane in UV‐irradiated cells. UV‐induced DMC did not dissociate when the cells were treated with inhibitors of DNA‐gyrase. It, therefore, was qualitatively different from the DMC found during replication. The mechanisms of binding of the damaged DNA to the membrane in UV‐irradiated cells of B. subtilis are discussed.