Temperature-sensitive mutation in lytF, a new gene involved in autolysis of Escherichia coli

A temperature-sensitive mutation in a new Escherichia coli gene, located at 62.5 min on the linkage map and designated lytF, resulted in bacteriolysis at the restrictive temperature. Temperature sensitivity and lytF-mediated lysis were simultaneously suppressed by either of two previously described unlinked mutations designated smhA1 and smhB1. The smhA1 and smhB1 alleles were originally isolated as specific extragenic suppressors of temperature-sensitive mutations in three other genes known as murH (99 min), lytD (13 min) and lytE (25 min) which conferred lysis phenotypes indistinguishable from that of the lytF mutation. The murH, lytD and lytE genes have been proposed to be related on the bases of phenotypic similarities and the specificities of their extragenic suppressors. It is now further proposed that lytF belongs to this group. The isolation of new alleles of smhA and smhB as extragenic suppressors of lytF further supports this proposal.