Cloning and deletion mapping of the recF dnaN region of the Escherichia coli chromosome.

By cloning a 3.6-kb EcoRI fragment of the Escherichia coli chromosome with pBR322 we located more precisely recF relative to dnaN. By deletion mapping we localized functional recF to a 1.65-kb region of the cloned fragment and allowed rough mapping of the C terminus of dnaN. Cloned recF+, separated from functional flanking genes dnaN and gyrB, complemented chromosomal recF mutations presumably by coding for a cytodiffusible product. The protein encoded by dnaN was observed as a band on a polyacrylamide gel from minicells. Identification of a recF protein was not made.