Evidence for alkali-sensitive linkers in DNA of African green monkey kidney cells


MITOCHONDRIAL DNA possesses ribonucleotide linkers1–3 and although double-stranded eukaryotic chromosomal DNA seems to be continuous throughout the length of the chromosome4 it is possible that single-stranded DNA possesses physical (nicks) or chemical (non-deoxynucleotide linkers) discontinuities. To distinguish between an in vivo nick and a nick introduced by shear forces during DNA extraction is very difficult with the presently available techniques. The detection of non-deoxynucleotide linkers is, however feasible, providing that denatured DNA can be sedimented in a chemical environment in which the linker is not destroyed. In these conditions, the comparison between sedimentation profiles of DNA, previously treated or not with a reagent that attacks the linker, may reveal the discontinuity. An obvious such reagent is a strong base, thus precluding the use of alkaline gradients in these experiments, and so we have attempted to use sucrose gradients in non-aqueous formamide. In addition, the DNA had to be extracted by a very gentle method in order to keep its average molecular weight in the range of 50–80 × 106. Using these conditions, we were able to detect alkali-sensitive linkers in chromosomal DNA of green monkey kidney cells.

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  1. 1

    Grossman, L. I., Watson, R. & Vinograd, J. Proc. natn. Acad. Sci. U.S.A. 70, 3339–3443 (1973).

  2. 2

    Miyaki, M., Koide, K. & Ono, T. Biochem. biophys. Res. Commun. 50, 252–258 (1973).

  3. 3

    Wong-Staal, F., Mendelsohn, J. & Goulian, M. Biochem. biophys. Res. Commun. 53, 140–148 (1973).

  4. 4

    Kavenoff, R. & Zimm, B. H. Chromosoma (Berl.) 41, 1–27 (1973).

  5. 5

    Huberman, J. A. & Riggs, A. D. J. molec. Biol. 32, 327–341 (1968).

  6. 6

    Lehmann, A. R. J. molec. Biol. 66, 319–337 (1972).

  7. 7

    Brutlag, D., Schekman, R. & Kornberg, A. Proc. natn. Acad. Sci. U.S.A. 68, 2826–2829 (1971).

  8. 8

    Sugino, A. & Okasaki, R. Proc. natn. Acad. Sci. U.S.A. 70, 88–92 (1973).

  9. 9

    Magnusson, G., Pigiet, V., Winnacker, E. L., Abrams, R. & Reichard, P. Proc. natn. Acad. Sci. U.S.A. 70, 412–415 (1973).

  10. 10

    Lindahl, T. & Nyberg, B. Biochemistry 11, 3610–3618 (1972).

  11. 11

    Hozier, J. C. & Taylor, J. H. J. molec. Biol. 93, 181–201 (1975).

  12. 12

    Fujiwara, Y. Cancer Res. 35, 2780–2789 (1975).

  13. 13

    Hershey, H. V. & Werner, D. Nature 262, 148–150 (1976).

  14. 14

    Meneghini, R. Biochim. biophys. Acta 425, 419–427 (1976).

  15. 15

    Studier, F. W. J. molec. Biol. 11, 373–390 (1965).

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FILIPPIDIS, E., MENEGHINI, R. Evidence for alkali-sensitive linkers in DNA of African green monkey kidney cells. Nature 269, 445–447 (1977). https://doi.org/10.1038/269445a0

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