DNA-Folding by a Stably DNA-Linked Protein in Eukaryotic Chromatin

  • Zoya Avramova
  • Peter Petrov
  • Roumen Tsanev


Higher levels of structural organization of DNA is achieved through its interaction with different proteins. These interactions are abolished by reagents destroying noncovalent associations, hydrogen bonding and S-S bridges. However, in chromatin of different origin a fraction of nonhistone proteins was found whose association with DNA could not be disrupted by such reagents (Lesko and Emery, 1966; Krauth and Werner, 1979; Neuer et al., 1983; Avramova and Tsanev, 1987). The presence of such a protein fraction was proved by in vitro iodination and by in vivo incorporation of labelled aminoacids. This firmly bound protein fraction showed several unusual properties: 1) After iodination it could not enter the Polyacrylamide gels upon electrophoresis. This made impossible the estimation of its molecular mass; 2) The two-dimensional tryptic peptide map of the iodinated protein isolated from eleven different chromatins — Drosophila, fish, frog and rat liver, chicken erythrocytes, rat and ram sperm, Guerin tumor cells, mouse Friend cells, maize leaves and roots — showed a practically identical pattern (Avramova et al., 1989a, b), revealing its high evolutionary conservation; 3) By in vivo labelling of DNA and of the protein it was found that this protein was metabolically stable, transmitted to the progeny like DNA (Avramova et al., 1988a); 4) Chemical and enzymic analysis of the DNA-protein linkage of the stable complex have suggested a bond of a phosphodiester type.


Protein Fraction Nuclear Matrix Phosphodiester Bond Sperm Chromatin Chromatin Loop 
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  1. Avramova Z., and Tsanev R. 1987, Stable DNA-protein complexes in eukaryotic chromatin, J. Mol. Biol., 196:437.PubMedCrossRefGoogle Scholar
  2. Avramova Z., Mikhailov I., and Tsanev R. 1988a, Metabolic behaviour of a stable DNA-protein complex, Int. J. Biochem., 20:61.PubMedCrossRefGoogle Scholar
  3. Avramova Z., Ivanchenko M., and Tsanev R. 1988b, A protein fraction stably linked to DNA in plant chromatin, Plant Mol. Biol., 11:401.CrossRefGoogle Scholar
  4. Avramova Z., Mikhailov I., and Tsanev R. 1989, An evolutionarily conserved protein fraction stably linked to DNA in eukaryotic chromatin, Biochim. Biophys. Acta, 1007:109.Google Scholar
  5. Comings D. E., and Okada T. A. 1976, Nuclear Proteins III. The fibrillar nature of the nuclear matrix, Exp. Cell Res., 103:341.PubMedCrossRefGoogle Scholar
  6. Gross D., and Garrard W. T. 1987, Poising chromatin for transcription, Trends Biochem. Sci., 12:293.CrossRefGoogle Scholar
  7. Kleinschmidt A.1968, Monolayer techniques in electron microscopy of nucleic acid molecules in: ‘Methods in Enzymology’ 12B, L. Grossman and K. Moldave, eds., Academic Press, New York and London.Google Scholar
  8. Krauth W., and Werner D. 1979, Analysis of the most tightly bound proteins in eukaryotic DNA, Biochim. Biophys. Acta, 564:390.Google Scholar
  9. Lesko S. A., and Emery A. J. 1966, Subunit form of calf thymus DNA, Biochem. Biophys. Res. Commun., 23:707.PubMedCrossRefGoogle Scholar
  10. Leon P., and Macaya G. 1983, Properties of DNA rosettes and their relevance to chromosome structure, Chromosoma, 88:307.CrossRefGoogle Scholar
  11. Neuer B., Plagens U., and Werner D. 1983, Phosphodiester bonds between polypeptides and chromosomal DNA, J. Mol. Biol. 164:213.PubMedCrossRefGoogle Scholar
  12. Okada T. A., and Comings D. E. 1979, Higher order structure of chromosomes, Chromosoma, 72:1.CrossRefGoogle Scholar
  13. Sonnenbichler J. 1969, Nucleoprotein complexes: Possible subunits of chromosomes, Hoppe-Seyler’s Z. Physiol. Chem., 350:761.PubMedCrossRefGoogle Scholar
  14. Zatsepina O. V., Polyakov V. Yu., and Chentsov Yu. S. 1983, Chromonema and chromomere. Structural units of mitotic and interphase chromosomes, Chromosoma, 88:91.CrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1990

Authors and Affiliations

  • Zoya Avramova
    • 1
  • Peter Petrov
    • 1
  • Roumen Tsanev
    • 1
  1. 1.Institute of Molecular BiologyBulgarian Academy of SciencesSofiaBulgaria

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