title: The mutation that makes Escherichia coli resistant to lambda P gene-mediated host lethality is located within the DNA initiator Gene dnaA of the bacterium.
abstract: Earlier, we reported that the bacteriophage lambda P gene product is lethal to Escherichia coli, and the E. coli rpl mutants are resistant to this lambda P gene-mediated lethality. In this paper, we show that under the lambda P gene-mediated lethal condition, the host DNA synthesis is inhibited at the initiation step. The rpl8 mutation maps around the 83 min position in the E. coli chromosome and is 94 % linked with the dnaA gene. The rpl8 mutant gene has been cloned in a plasmid. This plasmid clone can protect the wild-type E. coli from lambda P gene-mediated killing and complements E. coli dnaAts46 at 42 degrees C. Also, starting with the wild-type dnaA gene in a plasmid, the rpl-like mutations have been isolated by in vitro mutagenesis. DNA sequencing data show that each of the rpl8, rpl12 and rpl14 mutations has changed a single base in the dnaA gene, which translates into the amino acid changes N313T, Y200N, and S246T respectively within the DnaA protein. These results have led us to conclude that the rpl mutations, which make E. coli resistant to lambda P gene-mediated host lethality, are located within the DNA initiator gene dnaA of the host.
authors.affiliation: Department of Biochemistry, Bose Institute, Acharya J. C. Bose Birth Centenary Building, P-1/12, CIT Scheme VII M, Calcutta 700 054, India.
authors.forename: Indrani
authors.initials: I
authors.lastname: Datta
authors.forename: Sarbani
authors.initials: S
authors.lastname: Banik-Maiti
authors.forename: Lopa
authors.initials: L
authors.lastname: Adhikari
authors.forename: Subrata
authors.initials: S
authors.lastname: Sau
authors.forename: Niranjan
authors.initials: N
authors.lastname: Das
authors.forename: Nitai Chandra
authors.initials: NC
authors.lastname: Mandal
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D010582:Bacteriophage lambda / Q000235:genetics* / Q000472:pathogenicity; D002876:Chromosomes, Bacterial; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D005804:Genes, Lethal; D016296:Mutagenesis; D009154:Mutation / Q000235:genetics*; D010957:Plasmids; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria