title: Heat mutagenesis in bacteriophage T4: another walk down the transversion pathway.
abstract: Extracellular nonreplicating bacteriophage T4 particles accumulate mutations as functions of temperature, time, pH, and ionic environment via two mechanisms: 5-hydroxymethylcytidine deamination produces G.C----A.T transitions while a guanosine modification produces transversions. Neither frameshift mutations nor mutations at A.T base pairs are appreciably induced. We now show that heat induces G.C----T.A transversions which we suggest may arise via a G*.A mispair, in which G* is a modified guanosine that has experienced a glycosylic bond migration. The rate of this reaction at 37 degrees C is sufficient to present a genetic hazard, particularly to large genomes; thus, the lesion is probably efficiently repaired in cellular genomes.
authors.affiliation: Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709.
authors.forename: M C
authors.initials: MC
authors.lastname: Kricker
authors.forename: J W
authors.initials: JW
authors.lastname: Drake
mesh_terms: D001482:Base Composition; D005814:Genes, Viral; D006358:Hot Temperature; D009154:Mutation; D013604:T-Phages / Q000235:genetics*