Genetic analysis of mutations affecting ribonuclease II inEscherichia coli

Abstract

Exonuclease activity in anEscherichia coli K12 mutant S296 is less than 1% of that in the wild type strain (Nikolaev et al., 1976). Another mutant N464 has thermolabile ribonuclease II (Castles and Singer, 1968; Kuwano et al., 1969). Genetic analysis of these mutants by Hfr conjugation and P1 transduction indicates that the structural gene (rnb) for ribonuclease II is located near thepyrF gene (28 min on theE. coli genetic map of Bachmann, Low and Taylor (1976)), and the most probable gene order istyrT-trp-pyrF-rnb.