Postreplication repair: questions of its definition and possible alteration in xeroderma pigmentosum cell strains

Journal Article · Wed Aug 01 04:00:00 EDT 1979 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.76.8.3927· OSTI ID:5371234

Park, S D; Cleaver, J E

DNA synthesis in normal cells and in excision-defective and variant xeroderma pigmentosum cells was investigated after irradiation with ultraviolet light. The sizes of DNA synthesized during brief pulses of (/sup 3/H)thymidine 1 to 2 h after irradiation were decreased, the xeroderma pigmentosum variant showing the smallest molecular weight. Once synthesized, however, labeled DNA increased in size at the same rate as control in all cell strains, and the rate was relatively insensitive to caffeine. After 2 to 3 h, labeled DNA in each cell type reached a maximum size that was less than that in control cells, indicating the presence of long-lived blocks to DNA chain growth. This kind of experiment (pulse-chase) has in the past been used to investigate a repair process believed to be associated with the bypass of damaged sites in parental DNA: postreplication repair. We present an alternative model that does not involve a specific postreplication repair mechanism, but involves normal chain elongation and termination mechanisms in which we conceive that dimers and other damaged sites act as all-or-nothing blocks to the progress of replication forks. No evidence could be found for any inducible process that enhanced the bypass of damaged sites.

• Research Organization: Univ. of California, San Francisco
• OSTI ID: 5371234
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Journal Name: Proc. Natl. Acad. Sci. U.S.A.; (United States) Vol. 76:8; ISSN PNASA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
AZINES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BIOLOGICAL MODELS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BIOSYNTHESIS
CAFFEINE
DIMERS
DISEASES
DNA
DRUGS
ELECTROMAGNETIC RADIATION
HETEROCYCLIC COMPOUNDS
HYDROGEN ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIGHT NUCLEI
MOLECULAR WEIGHT
NUCLEI
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PURINES
PYRIMIDINES
RADIATION EFFECTS
RADIATIONS
RADIOISOTOPES
RADIOSENSITIVITY
REACTION KINETICS
RECOVERY
REPAIR
RIBOSIDES
SKIN DISEASES
SYNTHESIS
THYMIDINE
TOXICITY
TRACER TECHNIQUES
TRITIUM
ULTRAVIOLET RADIATION
XANTHINES
XERODERMA PIGMENTOSUM
XP CELLS
YEARS LIVING RADIOISOTOPES