Letter | Published:

Age-dependent excision repair of damaged thymine from γ-irradiated DNA by isolated nuclei from human fibroblasts


THE lifespan of diploid human fibroblasts in culture is limited1, although there are substantial variations in lifespan with different culturing conditions and growth media2–4. Before death, the cells pass through a period of senescence, characterised by numerous structural changes5. According to the error catastrophe hypothesis, a breakdown of the fidelity of the expression of genetic information resulting in the production of faulty proteins6–11, and the accumulation of mutations in the genome12, may represent important mechanisms of cellular ageing. It would be predicted that the deterioration of the quality of the genome would be accelerated by deficient or error-prone DNA repair. Several steps in the excision repair of damaged DNA residues have been demonstrated in mammalian cells exposed to exogenous physical or chemical agents. In the case of ionising radiation, the removal from the DNA of thymine damaged by γ rays was observed in Chinese hamster ovary13 and human WI-38 cells14, and the filling of the resulting gaps, indicated by repair replication or unscheduled synthesis, has been demonstrated in numerous cell lines15. Recently published experiments16 have demonstrated that the capacity of skin fibroblasts to perform ultraviolet-induced repair synthesis increases as a function of the lifespan of the donor species. We report that isolated nuclei or nuclear sonicates from senescent diploid human lung fibroblasts WI–38 have lost their ability to excise from DNA thymine damaged by γ rays.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Hayflick, L., Moorehead, P. S., Expl Cell. Res., 25, 585–621 (1961).

  2. 2

    Packer, L., and Smith, J. R., Proc. natn. Acad. Sci. U.S.A, 71, 4763–4767 (1974).

  3. 3

    Macieira-Coelho, A., Experientia, 22, 390–391 (1966).

  4. 4

    Cristofalo, V. J., in Ageing in Cell and Tissue Culture (edit. by Holeckova, E., and Cristofalo V. J.) (Plenum, New York, 1970).

  5. 5

    Lipetz, J., and Cristofalo, V. J., J. Ultrastruct. Res., 39, 43–55 (1972).

  6. 6

    Wang, K-M, Rose, N. R., Bartholomew, E. A., Balzer, M., Berde, K., and Foldvary, M., Expl Cell. Res., 61, 357–364 (1970).

  7. 7

    Cristofalo, V. J., Parris, N., and Kritchevsky, D., J. Cell Physiol., 69, 263–271 (1967).

  8. 8

    Holliday, R., and Tarrant, G. M., Nature, 238, 26–30 (1972).

  9. 9

    Holliday, R., Nature, 248, 762–763 (1974).

  10. 10

    Orgel, L. E., Proc. natn. Acad. Sci. U.S.A., 49, 517–521 (1963).

  11. 11

    Orgel, L. E., Nature, 244, 441–445 (1973).

  12. 12

    Curtis, H. J., Adv. Genet., 16, 305–324 (1971).

  13. 13

    Mattern, M. R., Hariharan, P. V., Dunlap, B. E., and Cerutti, P. A., Nature new Biol., 245, 230–232 (1973).

  14. 14

    Cerutti, P. A., Naturwissenchaften, 61, 51–59 (1974).

  15. 15

    Painter, R. B., current Topics in Radiation Research, 7, 45–70 (1970).

  16. 16

    Hart, R. W., and Setlow, R. B., Proc. natn. Acad. Sci. U.S.A., 71, 2169–2173 (1974).

  17. 17

    Cristofalo, V. J., and Sharf, B., Expl Cell. Res., 76, 419–427 (1973).

  18. 18

    Painter, R. B., Clarkson, J. M., and Young, B. R., Rad. Res., 56, 560–564 (1973).

  19. 19

    Clarkson, J. M., and Painter, R. B., Mut. Res., 23, 107–112 (1974).

  20. 20

    Hart, R., and Setlow, R. B., in Fifth Int. Congr. Rad. Res. Seattle, (1974).

  21. 21

    Berkowitz, D. M., Kakefuda, T., and Sporn, M. B., J. Cell. Biol., 42, 851–855 (1969).

  22. 22

    Franklin, R., Salditt, M., and Silbert, J., Virology, 38, 627–640 (1968).

  23. 23

    Hariharan, P. V., and Cerutti, P. A., Proc. natn. Acad. Sci. U.S.A, 71, 3532–3536 (1974).

  24. 24

    Dunlap, B. E., and Cerutti, P. A., FEBS Lett. (in the press).

  25. 25

    Beer, M., Stern, S., Carmalt, D., and Mohlenrich, K., Biochemistry, 5, 2283–2288 (1966).

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.