title: Genetic mapping of xthA, the structural gene for exonuclease III in Escherichia coli K-12.
abstract: The genes xthA, pncA, and pabB were ordered relative to others by two- and three-factor transductional crosses with bacteriophage P1. The genes studied span 2 min (2%) of the genetic map of Escherichia coli K-12 in the clockwise sequence pheS-pfkB-xthA-pncA-gap-pabB-fadD. Eleven independently derived xth mutations were examined; all were known to affect exonuclease III and its associated endonuclease II activity, and all were mapped in the xthA region. pncA mutations were found to confer resistance to 6-aminonicotinamide, whereas some pheS mutations are known to specify resistance to p-fluorphenylalanine. xth mutations were readily transferred into other strains by selecting for these co-transducible drug resistance markers.
mesh_terms: D015120:6-Aminonicotinamide / Q000494:pharmacology; D002874:Chromosome Mapping; D003851:Deoxyribonucleases / Q000096:biosynthesis; D004352:Drug Resistance, Microbial; D004720:Endonucleases / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology*; D005092:Exonucleases / Q000096:biosynthesis*; D005796:Genes; D014161:Transduction, Genetic; D010135:p-Fluorophenylalanine / Q000494:pharmacology
chemical_list: D015120:6-Aminonicotinamide; D010135:p-Fluorophenylalanine; D003851:Deoxyribonucleases; D004720:Endonucleases; D005092:Exonucleases