title: Suppressible and nonsuppressible +1 G-C base pair insertions induced by ICR-170 at the his4 locus in Saccharomyces cerevisiae.
abstract: Fifteen independent ICR-170-induced his4 mutations in Saccharomyces cerevisiae were examined by DNA sequence analysis. All of the mutations contained a +1 G-C base pair addition in the HIS4 coding region. Eleven different sites of insertion were identified. Combined with previous DNA sequence data, 21 ICR-170-induced his4 mutations distributed at 16 different sites were analyzed. The insertions were always located in a consecutive run of two or more G-C base pairs, with all base pairs in each run having identical orientation. Long consecutive G-C runs were preferred target sites over short runs. Although some consecutive G-C runs appeared to be preferred target sites over others of identical length, such preference was not due to any particular type of nucleotide pair immediately adjacent to a given target site. In addition, DNA sequence analyses of the his4 mutations provided a basis for examining the mechanism of mRNA sequence recognition by extragenic suppressors of ICR-170-induced mutations. The implications of these results for mechanisms of frameshift suppression are discussed.
mesh_terms: D000609:Aminoacridines; D001482:Base Composition; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000032:analysis; D005800:Genes, Fungal / Q000187:drug effects; D009154:Mutation; D009588:Nitrogen Mustard Compounds / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics*; D013489:Suppression, Genetic
chemical_list: D000609:Aminoacridines; D004271:DNA, Fungal; D009588:Nitrogen Mustard Compounds; C091910:acridine mustard