title: Isolation and characterization of phi X174 mutants carrying lethal missense mutations in gene G.
abstract: A previously constructed Escherichia coli transformant carrying a functional copy of bacteriophage phi X174 gene G on a plasmid, p phi XG, was used to isolate gene G mutants carrying temperature sensitive and lethal missense mutations. Two of the mutations have been characterized by sequencing: one carries a G --> A transition at residue 2821 producing a Gly --> Ser change in codon 143 of the G spike protein; the other carries an A --> G transition at residue 2678 producing Glu --> Gly change in codon 95. Sequencing DNA from 2 other mutants carrying lethal mutations that are rescued with p phi XG did not reveal any changes in the coding sequence. The lesion is believed to be in the intercistronic region between genes F and G. The adsorption kinetics for these mutants appear to be normal. Their burst size is about 25% that of wild type phi X174 on the host carrying p phi XG. These results along with previous results from the senior author's laboratory demonstrate that p phi XG can be used to rescue any gene G mutant of phi X174 regardless of the nature of the mutation involved.
mesh_terms: D010584:Bacteriophage phi X 174 / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D003062:Codon / Q000235:genetics; D004262:DNA Restriction Enzymes; D004926:Escherichia coli / Q000235:genetics*; D005804:Genes, Lethal; D005814:Genes, Viral; D009154:Mutation; D010957:Plasmids; D013696:Temperature
chemical_list: D003062:Codon; D004262:DNA Restriction Enzymes