Mechanisms of mutagenesis for lambda phage

Journal Article · Sat Jan 01 04:00:00 EST 1983 · UCLA Symp. Mol. Cell. Biol., New Ser.; (United States)

OSTI ID:6539528

Hutchinson, F; Skopek, T R; Wood, R D

The principal experimental results are determination of the changes in DNA base sequence resulting from forward mutations in the cI (repressor) gene of lambda phage induced by various agents. For phage irradiated with ultraviolet light and assayed in lightly irradiated host cells to induce Weigle mutagenesis (targeted mutagenesis), two-thirds of the mutations are transitions. Most transitions seem to arise at the sites of Py(6-4)Pyo photoproducts, not at the more widely studied cyclobutane pyrimidine dimers. The other mutations induced by ultraviolet are equally divided among transversions, frameshifts and double mutation events. The latter, two closely spaced base changes or a base change plus a frameshift, should rarely revert and may be the deletions induced by ultraviolet which have been previously reported. Unirradiated phage assayed in host cells heavily irradiated with ultraviolet light (nontargeted mutagenesis) show mainly frameshift mutations. These frameshifts may arise from low intracellular activity of DNA polymerase I when the enzyme binds to host DNA damaged by irradiation of the cells. Mismatch repair greatly reduced the numbers of mutations from bromouracil (which induces transitions by base mispairing) and acridines which induce frameshifts at runs of G.C base pairs). Only when mismatch repair activity is saturated by the number of improperly stacked bases in the DNA does a high level of mutagenesis occur.

• Research Organization: Yale Univ., New Haven, CT
• OSTI ID: 6539528
• Journal Information: UCLA Symp. Mol. Cell. Biol., New Ser.; (United States), Journal Name: UCLA Symp. Mol. Cell. Biol., New Ser.; (United States) Vol. 11; ISSN USMBD
• Country of Publication: United States
• Language: English

Related Subjects

560121* -- Radiation Effects on Cells-- External Source-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BACTERIOPHAGES
BIOASSAY
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CHEMICAL REACTIONS
DAMAGE
DNA
ELECTROMAGNETIC RADIATION
ENZYME ACTIVITY
ENZYMES
MICROORGANISMS
MUTAGENESIS
NUCLEIC ACIDS
NUCLEOTIDYLTRANSFERASES
ORGANIC COMPOUNDS
PARASITES
PHOSPHORUS-GROUP TRANSFERASES
PHOTOCHEMICAL REACTIONS
POLYMERASES
RADIATIONS
RECOVERY
REPAIR
TRANSFERASES
ULTRAVIOLET RADIATION
VIRUSES