Open AccessIsolation and characterization of conditional-lethal rho mutants of Escherichia coli.
Author(s) -
Hidetoshi Inoko,
Katsuya Shigesada,
Masayuki Imai
Publication year - 1977
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.74.3.1162
Subject(s) - mutant , lambda phage , escherichia coli , gene , transcription (linguistics) , temperature sensitive mutant , biology , lambda , genetics , microbiology and biotechnology , dna , genome , bacteria , chemistry , bacteriophage , physics , linguistics , philosophy , optics
Temperature-sensitive nitA (rho) mutants of E. coli were isolated; one of them was characterized as an amber mutant. These strains show the Nit phenotype (transcription of phage lambda DNA independent of the N gene) at low temperatures and are inviable at high temperatures. The mutated sites appear to be between cya and metE on the chromosome. Temperature-sensitive nitA bacteria not only permit leftward transcription of the lambda genome at a high rate in the absence of the lambda N protein, but also allow lambda growth at low temperatures. At high temperatures, phages lambda and T4 are incapable of normal development in these cells, while growth of T7 is not affected. The production of thermally unstable rho by the nitA temperature-sensitive mutant suggests that nitA is the structural gene for rho.