Excision-Repair of γ-Ray-Damaged Thymine in Bacterial and Mammalian Systems
The selective excision of products of the 5,6-dihydroxy-dihydrothymine type (t′) from γ-irradiated or 0s04-oxidized DNA or synthetic poly[d(A-T)] was observed with crude extracts of Escherichia coli and isolated nuclei from human carcinoma HeLa S-3 cells and Chinese hamster ovary cells.
The results with E. coli extracts allow the following conclusion: (1) The uvrA-gene product is not required for t′ excision. (2) Radiation-induced strand breakage is not required for product excision. (3) Experiments with extracts of E. coli polAexl showed that the 5′→3′ exonuclease associated with polymerase I is responsible for the removal of t′. (4) Experiments with extracts of E. coli endo I rig 4 and the ligase inhibitor nicotinamide mononucleotide showed that polynucleotide ligase accomplishes the last strand resealing step in the excision-repair of t′.
Isolated nuclei from HeLa and Chinese hamster ovary cells possess the necessary enzymes for the selective excision of t′ from γ-irradiated or osmium tetroxide oxidized DNA. Approximately 25 to 35% of the products were removed from DNA within 60 min. Unspecific DNA degradation was very low. Radiation-induced strand breakage is not required for product removal.
KeywordsBase Damage Strand Breakage Thymine Residue Repair Replication Product Excision
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- Brent, T. (1973). Biophys. J. 13, 399–401.Google Scholar
- Campbell, J., Fleischman, A. and Richardson, C. (1971). Fed. Proc. 30, 1313 (abstr.).Google Scholar
- Cerutti, P. (1975a). In Photochemistry and Photobiology of Nucleic Acids (Wang, S. Y. & Patrick, M., eds.) Gordon Breach, New York (in press).Google Scholar
- Cleaver, J. (1969). Proc. Nat. Acad. Sci. U.S.A. 63, 428–435.Google Scholar
- Cleaver, J. (1974). Advan. Radiat. Biol. 4, 1–75.Google Scholar
- Freifelder, D. (1965). Proc. Nat. Acad. Sci. U.S.A. 54, 128–134.Google Scholar
- Gellert, M. and Bullock, M. (1970). Proc. Nat. Acad. Sci. U.S.A. 67, 1580–1587.Google Scholar
- Hariharan, P. and Cerutti, P. (1972). J. Mol. Bio!. 66, 65–81.Google Scholar
- Hariharan, P. and Cerutti, P. (1974a). Proc. Nat. Acad. Sci. U.S.A. 71, 3532–3536.Google Scholar
- Konrad, E. and Lehman, I. (1974). Proc. Nat. Acad. Sci. U.S.A. 71, 2048–2051.Google Scholar
- Mattem, M., Hariharan, P., Dunlop, B. and Cerutti, P. (1973). Nature New Biol. 245, 230–232.Google Scholar
- Painter, R. (1970). Curr. Top. Radiat. Res. 7, 45–70.Google Scholar
- Painter, R. (1972). Johns Hopkins Med. J. 1 (Suppl.), 140–146.Google Scholar
- Paterson, M. and Setlow, R. (1972). Proc. Nat. Acad. Sci. U.S.A. 69, 2927–2931.Google Scholar
- Regan, J. and Setlow, R. (1973). In Chemical Mutagens (Hollaender, A., ed.), vol. 3, pp. 151–170. Plenum Press, New York.Google Scholar
- Roti Roti, J. and Cerutti, P. (1974). Int. J. Radiat. Bio!. 35, 413–417.Google Scholar
- Setlow, R. and Regan, J. (1973) Biophys. Soc. Abst. 307a Biophys. J. 13.Google Scholar
- Wickner, R., Wright, M., Wickner, S. and Hurwitz, J. (1972). Proc. Nat. Acad. Sci. U.S.A. 69, 3233–3237.Google Scholar