Abstract
Genome exposure studies were carried out on malignant CHO-K1 and C6 rat glioma cells and their respective, phenotypically normal counterparts (reverse-transformed CHO-K1, and both reverse-transformed C6 glioma and normal rat fibroblasts). Cells were subjected to the nick-translation technique previously developed to make visible the exposed (i.e., DNase I-sensitive) nuclear DNA, and examined by both epifluorescence and confocal microscopy. The confocal microscopy, by permitting examination of sections throughout the nucleus, made possible clearer identification of the regions of exposed and sequestered DNA in the cells studied. A peripheral shell of exposed DNA with some discontinuities was displayed in the great majority of the cells with normal phenotype, but in none of the cancer cells. Both types of cells displayed regions of exposed DNA in the nuclear interior, particularly surrounding the nucleoli. In accordance with previous theoretical proposals we postulate: the peripheral nuclear shell of exposed DNA contains differentiation-specific genes that include the specific growth-control genes and that are functional in normal cells but not in cancer; the exposed genes surrounding the nucleoli may represent housekeeping genes active in both normal and cancer cells; and the DNase I-resistant DNA in the interior of the nucleus we postulate to consist for the most part of genes specific to alternative differentiation states and to be sequestered and inactive. Previous differences in evaluation of roles of peripheral and internal DNA sensitivity to DNase I hydrolysis appear to be reconciled by this formulation. Identification of exposed DNA may be useful in cancer diagnosis.
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Literature cited
Hsie, A.W., and Puck, T.T.Proc. Natl. Acad. Sci. U.S.A. (1971).Proc. Natl. Acad. Sci. U.S.A. 68358–361.
Puck, T.T. (1977).Proc. Natl. Acad. Sci. U.S.A. 744491–4495.
Puck, T.T. (1984).Adv. Viral Oncol. 4197–216.
Schonberg, S., Patterson, D., and Puck, T.T. (1983).Exp. Cell Res. 14557–62.
Ashall, F., and Puck, T.T. (1984).Proc. Natl. Acad. Sci. U.S.A. 815145–5149.
Puck, T.T., Krystosek, A., and Chan, D. (1990).Somat. Cell Mol. Genet. 16257–265.
Puck, T.T., and Krystosek, A. (1992).Int. Rev. Cytol. (in press).
Ashall, F., Sullivan, N., and Puck, T.T. (1988).Proc. Natl. Acad. Sci. U.S.A. 853908–3912.
Krystosek, A., and Puck, T.T. (1990).Proc. Natl. Acad. Sci. U.S.A. 876560–6564.
Hutchison, N., and Weintraub, H. (1985).Cell 43471–482.
Manuelidis, L., and Borden, J. (1988).Chromosoma 96397–410.
Tjio, J.H., and Puck, T.T. (1958).J. Exp. Med. 108259–268.
Hsie, A.W., Jones, C., and Puck, T.T. (1971).Proc. Natl. Acad. Sci. U.S.A. 681648–1652.
Benda, P., Lightbody, L., Sato, G., Levine, L. and Sweet, W. (1968).Science 161370.
Topp, W.C. (1981).Virology 113408–411.
White, J.G., Amos, W.B., and Fordam, M. (1987).J. Cell Biol. 10541–48.
Shotton, D.M. (1989).J. Cell Sci. 94175–206.
Krystosek, A., and Puck, T.T. (1989).J. Cell Biol. 109:231a.
Gerace, L., and Blobel, G. (1980).Cell 19277–287.
Paddy, M.R., Belmont, A.S., Saumweber, H., Agard, D.A., and Sedat, J.W. (1990).Cell 6289–106.
Garel, A., and Axel, R. (1976).Proc. Natl. Acad. Sci. U.S.A. 733966–3970.
Clark, R.F., Cho, K.W.Y., Weinmann, R., and Hamkalo, B.A. (1991).Gene Express. 161–70.
Spector, D.L. (1990).Proc. Natl. Acad. Sci. U.S.A. 87147–151.
Blobel, G. (1985).Proc. Natl. Acad. Sci. U.S.A. 828527–8529.
de Graaf, A., van Hemert, F., Linnemans, W.A.M., Brakenhoff, G.J., de Jong, L., van Renswoude, J., and van Driel, R. (1990).Eur. J. Cell Biol. 52135–141.
Mummery, C.L., Feijen, A., van der Saag, P.T., van den Brink, C.E., and de Laat, S.W. (1985).Dev. Biol. 109402–410.
White, E., and Cipriani, R. (1989).Proc. Natl. Acad. Sci. U.S.A. 869886–9890.
White, E., and Cipriani, R. (1990).Mol. Cell. Biol. 10120–130.
Chou, C.C., Davis, R.C., Fuller, M.L., Slovin, J.P., Wong, A., Wright, J., Kania, S., Shaked, R., Gatti, R.A., and Salser, W.A. (1987).Proc. Natl. Acad. Sci. U.S.A. 842575–2579.
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Puck, T.T., Bartholdi, M., Krystosek, A. et al. Confocal microscopy of genome exposure in normal, cancer, and reverse-transformed cells. Somat Cell Mol Genet 17, 489–503 (1991). https://doi.org/10.1007/BF01233173
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DOI: https://doi.org/10.1007/BF01233173