One pyrimidine dimer inactivates expression of a transfected gene in xeroderma pigmentosum cells

Journal Article · Tue Oct 01 00:00:00 EDT 1985 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.82.19.6622· OSTI ID:6082069

Protic-Sabljic, M; Kraemer, K H

The authors have developed a host cell reactivation assay of DNA repair utilizing UV-treated plasmid vectors. The assay primarily reflects cellular repair of transcriptional activity of damaged DNA measured indirectly as enzyme activity of the transfected genes. They studied three plasmids (pSV2cat, 5020 base pairs; pSV2catSVgpt, 7268 base pairs; and pRSVcat, 5027 base pairs) with different sizes and promoters carrying the bacterial cat gene (CAT, chloramphenicol acetyltransferase) in a construction that permits cat expression in human cells. All human simian virus 40-transformed cells studied expressed high levels of the transfected cat gene. UV treatment of the plasmids prior to transfection resulted in differential decrease in CAT activity in different cell lines. With pSV2catSVgpt, UV inactivation of CAT expression was greater in the xeroderma pigmentosum group A and D lines than in the other human cell lines tested. The D0 of the CAT inactivation curve was 50 J X m-2 for pSV2cat and for pRSVcat in the xeroderma pigmentosum group A cells. The similarity of the D0 data in the xeroderma pigmentosum group A cells for three plasmids of different size and promoters implies they all have similar UV-inactivation target size. UV-induced pyrimidine dimer formation in the plasmids was quantified by assay of the number of UV-induced T4 endonuclease V-sensitive sites. In the most sensitive xeroderma pigmentosum cells, with all three plasmids, one UV-induced pyrimidine dimer inactivates a target of about 2 kilobases, close to the size of the putative CAT mRNA.

• Research Organization: National Cancer Institute, Bethesda, MD
• OSTI ID: 6082069
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 19
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
HOST-CELL REACTIVATION
BIOASSAY
PYRIMIDINE DIMERS
RADIOINDUCTION
TRANSFERASES
INACTIVATION
DNA REPAIR
FIBROBLASTS
GENES
PLASMIDS
ULTRAVIOLET RADIATION
XERODERMA PIGMENTOSUM
XP CELLS
ANIMAL CELLS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CELL CONSTITUENTS
CONNECTIVE TISSUE CELLS
DISEASES
ELECTROMAGNETIC RADIATION
ENZYMES
RADIATIONS
RECOVERY
REPAIR
SKIN DISEASES
SOMATIC CELLS
560121* - Radiation Effects on Cells- External Source- (-1987)