Mapping of a mutation, polB100, affecting deoxyribonucleic acid polymerase II in Escherichia coli K-12.

Direct assay for deoxyribonucleic acid polymerase II in extracts has been used to screen recombinants for the polB allele in Hfr x F(-) crosses, F-ductants in episome transfer, and transductants in generalized transduction by phage P1. The polB gene is located at 2 min on the Escherichia coli linkage map; it is 39 to 64% co-transducible with leu. A mutant, E. coli polA1 polB100 polC (ts), deficient in deoxyribonucleic acid polymerases I and II and having a thermolabile deoxyribonucleic acid polymerase III, has been prepared by the P1-mediated cross: P1 (HMS85 polB100) x E. coli BT1026 polA1 polC (ts) leu(-).