title: Salmonella typhimurium prfA mutants defective in release factor 1.
abstract: Mutations have been characterized that map in the prfA gene of Salmonella typhimurium. These weak amber suppressors show increased readthrough of UAG but not UAA or UGA codons. Some hemA mutants exhibit a similar suppressor activity due to transcriptional polarity on prfA. All of the suppressors mapping in prfA are recessive to the wild type. Two mutant prfA genes were cloned onto plasmids, and their DNA sequences were determined. A method was devised for transferring the sequenced mutant alleles back to their original location in S. typhimurium via an Escherichia coli recD strain that carries the entire S. typhimurium hemA-prfA operon as a chromosomal insertion in trp. This reconstruction experiment showed that the mutations sequenced are sufficient to confer the suppressor phenotype.
authors.affiliation: Department of Microbiology, University of Alabama, Birmingham 35294.
authors.forename: T
authors.initials: T
authors.lastname: Elliott
authors.forename: X
authors.initials: X
authors.lastname: Wang
mesh_terms: D003001:Cloning, Molecular; D003062:Codon; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D007763:Lac Operon; D005810:Multigene Family; D009154:Mutation; D010454:Peptide Termination Factors / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid; D012486:Salmonella typhimurium / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification; D013489:Suppression, Genetic
chemical_list: D003062:Codon; D029968:Escherichia coli Proteins; D010454:Peptide Termination Factors; C489005:prfA protein, E coli