Abstract
The human TK6 lymphoblast cell line is heteroallelic at the thymidine kinase (TK) locus, with one functional and one nonfunctional allele. Cells that have undergone loss of heterozygosity (LOH) atTK can be selected and cloned in an in vitro assay. In order to study the extent of LOH, we have analyzed a total of 166 thymidine kinase-deficient mutants that arose either spontaneously or following induction by X-ray or ethyl methane sulfonate (EMS) using DNA probes in and around theTK gene on chromosome 17. Two distinct groups of mutants with different doubling times were identified. Among slow-growth mutants, the predominant change for both spontaneous and induced mutants was LOH that generally extended through the entireTK gene to both proximal and distal markers on 17q. While the majority of both spontaneous and X-ray-induced normal-growth mutants showed LOH, this was considerably more localized in scale for X-ray-induced mutants, which rarely involved the distal marker. LOH was rare among EMS-induced normal-growth mutants. LOH was never observed with a 17p marker, indicating that nondisjunctional events were not involved in any of the mutant clones examined. Densitometric analysis of the LOH mutants indicated mitotic recombination was a likely mechanism in more than half the spontaneous LOH mutants in both groups, whereas most induced mutants appeared to arise from simple deletions.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Literature cited
Knudson, A.G., Jr. (1986).Annu. Rev. Genet. 20231–251.
Sager, R. (1989).Science 2461406–1412.
Levine, A.J., and Momand, J. (1990).Biochim. Biophys. Acta 1032119–136.
Stanbridge, E.J. (1990).Annu. Rev. Genet. 24615–657.
Scrable, H.J., White, D.P., Lampkin, B.C., and Cavenee, W.K. (1987).Nature 329645–647.
Mulligan, L.M., Matlashewski, G.J., Scrable, H.J., and Cavenee, W.K. (1990).Proc. Natl. Acad. Sci. U.S.A. 875863–5867.
Liber, H.L., and Thilly, W.G. (1982).Mutat. Res. 94467–485.
Yandell, D.W., Dryja, T.P., and Little, J.B. (1990).Mutat. Res. 22989–102.
Yandell, D.W., and Little, J.B. (1986).Cancer Genet. Cytogenet. 20231–239.
Yandell, D.W., Dryja, T.P., and Little, J.B. (1986).Somat. Cell Mol. Genet. 12255–263.
Liber, L.L., Yandell, D.W., and Little, J.B. (1989).Mutat. Res. 2169–17.
Little, J.B., Yandell, D.W., and Liber, H.L. (1987).Banbury Report 28: Mammalian Cell Mutagenesis (Cold Spring Harbor Laboratory, Cold Spring Harbor, New York), pp. 225–236.
Liber, H.L., Call, K.M., Mascioli, D.A., and Thilly, W.G. (1985).Mutat. Res. 15195–108.
Furth, E.E., Thilly, W.G., Penman, B.W., Liber, H.L., and Rand, W.M. (1981).Anal. Biochem. 1101–8.
Nakamura, Y., Leppert, M., O'Connell, P., Wolff, R., Holm, T., Culver, M., Martin, C., Fujimoto, E., Hoff, M., Kumlin, E., and White, R. (1987).Science 2351616–1622.
Nakamura, Y., Lathrop, M., O'Connell, P., Leppert, M., Baker, D., Wright, E., Skolnick, M., Kondoleon, S., Litt, M., Lalouel, J., and White, R. (1988).Genomics 2302–309.
Bradshaw, H.D., Jr., and Deininger, P.L. (1984).Mol. Cell. Biol. 42316–2320.
Southern, E.M. (1975).J. Mol. Biol. 98503–517.
Hall, J.M., Lee, M.K., Newman, B., Morrow, J.E., Anderson, L.A., Huey, B., and King, M.K. (1990).Science 2501684–1689.
Applegate, M.L., Moore, M.M., Broder, C.B., Burrel, A., Juhn, G., Kasweck, K., Lin, P., Wadhams, A., and Hozier, J. (1990).Proc. Natl. Acad. Sci. U.S.A. 8751–55.
Stern, C. (1936).Genetics 21625–730.
Meselson, M.S., and Radding, C.M. (1975).Proc. Natl. Acad. Sci. U.S.A. 72358–361.
Szostak, J.W., Orr-Weaver, T.L., Rothestein, R.J., and Stahl, F.W. (1983).Cell 3325–35.
Liskay, R.M., and Stachelek, J.L. (1983).Cell 35157–165.
Wasmuth, J.J., and Hall, L.V. (1984).Cell 36697–707.
Potter, T.A., Zeff, R.A., Frankel, W., and Rajan, T.V. (1987).Proc. Natl. Acad. Sci. U.S.A. 841634–1637.
Groden, J., Nakamura, Y., and German, J. (1990).Proc. Natl. Acad. Sci. U.S.A. 874315–4319.
Turner, D.R., Grist, S.A., Janatipourt, M., and Morley, A.A. (1988).Proc. Natl. Acad. Sci. U.S.A. 853189–3192.
Morley, A.A., Grist, A.A., Turner, D.R., Kutlaca, A., and Bennet, G. (1990).Cancer Res. 504584–4587.
Amundson, S.A., Benjamin, M., Little, J.B., and Liber, H.L. (1991).Nucleic Acids Res. 193748.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Li, CY., Yandell, D.W. & Little, J.B. Molecular mechanisms of spontaneous and induced loss of heterozygosity in human cells in vitro. Somat Cell Mol Genet 18, 77–87 (1992). https://doi.org/10.1007/BF01233450
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF01233450