Sequence specificity of point mutations induced during passage of a UV-irradiated shuttle vector plasmid in monkey cells

Journal Article · Wed Jan 01 04:00:00 EST 1986 · Mol. Cell. Biol.; (United States)

DOI:https://doi.org/10.1128/MCB.6.1.277· OSTI ID:6841257

Hauser, J; Seidman, M M; Sidur, K; Dixon, K

A simian virus 40-based shuttle vector was used to characterize UV-induced mutations generated in mammalian cells. The small size and placement of the mutagenesis marker (the supF suppressor tRNA gene from Escherichia coli) within the vector substantially reduced the frequency of spontaneous mutations normally observed after transfection of mammalian cells with plasmid DNA; hence, UV-induced mutations were easily identified above the spontaneous background. UV-induced mutations characterized by DNA sequencing were found primarily to be base substitutions; about 56% of these were single-base changes, and 17% were tandem double-base changes. About 24% of the UV-induced mutants carried multiple mutations clustered within the 160-base-pair region sequenced. The majority (61%) of base changes were the G . C----A . T transitions; the other transition (A . T----G . C) and all four transversions occurred at about equal frequencies. Hot spots for UV mutagenesis did not correspond to hot spots for UV-induced photoproduct formation (determined by a DNA synthesis arrest assay); in particular, sites of TT dimers were underrepresented among the UV-induced mutations. These observations suggest to us that the DNA polymerase(s) responsible for mutation induction exhibits a localized loss of fidelity in DNA synthesis on UV-damaged templates such that it synthesizes past UV photoproducts, preferentially inserting adenine, and sometimes misincorporates bases at undamaged sites nearby.

• Research Organization: National Institute of Child Health and Human Development, Bethesda, MD
• OSTI ID: 6841257
• Journal Information: Mol. Cell. Biol.; (United States), Journal Name: Mol. Cell. Biol.; (United States) Vol. 1; ISSN MCEBD
• Country of Publication: United States
• Language: English

Related Subjects

560120* -- Radiation Effects on Biochemicals
Cells
& Tissue Culture
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
BACTERIA
BIOLOGICAL EFFECTS
CELL CONSTITUENTS
DNA POLYMERASES
DNA SEQUENCING
ELECTROMAGNETIC RADIATION
ENZYMES
ESCHERICHIA COLI
GENE MUTATIONS
GENETIC EFFECTS
MICROORGANISMS
MUTAGENESIS
MUTATIONS
NUCLEOTIDYLTRANSFERASES
PARASITES
PHOSPHORUS-GROUP TRANSFERASES
PLASMIDS
POLYMERASES
RADIATIONS
STRUCTURAL CHEMICAL ANALYSIS
TRANSFERASES
ULTRAVIOLET RADIATION
VIRUSES