Abstract
Chromatin structure can be probed by cross-linking DNA in situ using trioxsalen and irradiation with UV light. Presumably DNA within a nucleosome is protected from cross-linking so that this region appears as a single-strand loop in the electron microscope under a condition in which single-strands and double-strands are distinguished. Unprotected regions appear as duplex due to cross-linking.
We have used this approach to investigate the structure of chromatins containing satellite DNAs of Drosophila nasutoides. We have previously shown that D. nasutoides has an unusually large autosome pair which is almost entirely heterochromatic. Its nuclear DNA reveals four major satellite components amounting up to 60% of the total genome. All of them are localized in this large heterochromatic chromosome. We wish to ask whether chromatins containing different satellite sequences have different arrangements of nucleosomes. Our results from cross-linking experiments show that all DNA components including main band DNA have different patterns of protected and unprotected regions: (a) The length distributions of protected regions show multiple peaks with the smallest unit lengths being 200 nucleotides for main band DNA, 180 for satellites I, II and III, and 160 for satellite IV. (b) The amounts of unprotected regions, presumably internucleosome DNA, vary from 16% for main band DNA to 60% for satellite IV, suggesting that satellite chromatins have fewer nucleosomes per given length of chromatin than main band DNA chromatin. The spacings between nucleosomes appear to be random in satellite chromatins.
Similar content being viewed by others
References
Cole, R.S.: Psoralen monoadducts and interstrand cross-links in DNA. Biochim. biophys. Acta (Amst.) 254, 30–39 (1975)
Cordeiro, M., Wheeler, L., Lee, C.S., Kastritsis, D.C., Richardson, R.H.: Heterochromatic chromosomes and satellite DNAs of Drosophila nasutoides. Chromosoma (Berl.) 51, 65–73 (1975)
Cordeiro-Stone, M., Lee, C.S.: Studies on the satellite DNAs of Drosophila nasutoides: Their buoyant densities, melting temperatures, reassociation rates and localizations in polytene chromosomes. J. molec. Biol. 104, 1–24 (1976)
Davidson, N., Widholm, J., Nandi, U.S., Jensen, R., Olivera, B.M., Wang, J.C.: Preparation and properties of native crab dAT. Proc. nat. Acad. Sci. (Wash.) 53, 11–118 (1965)
Davis, R.W., Simon, M., Davidson, N.: Electron microscope heteroduplex methods for mapping regions of base sequence homology in nucleic acids. Methods in Enzyrnol., vol. 21, Part D (L. Grossman and K. Moldave, eds.), pp. 413–128 (1971)
Gray, D.M., Lee, C.S., Skinner, D.M.: First-neighbor frequencies of satellite DNA's from Drosophila nasutoides and Pagurus pollicaris from an analysis of their circular dichroism spectra. Biopolymers (in press, 1977)
Hanson, C.V., Shen, C.K.J., Hearst, J.E.: Cross-linking of DNA in situ as a probe for chromatin structure. Science 193, 62–64 (1976)
Hewish, D.R., Burgoyne, L.A.: Chromatin structure. The digestion of chromatin DNA at regularly spaced sites by nuclear deoxyribonuclease Chem. biophys. Res. Commun. 52, 504–510 (1973)
Holde, K.E., Van, Sahasrabuddhe, C.G., Shaw, B.: A model for particulate structure in chromatin. Nucl. Acids Res. 1, 1579–1586 (1974)
Kornberg, R.D.: Chromatin structure: a repeating unit of histones and DNA. Science 184, 868–871 (1974)
Lee, C.S.: DNA synthesis in larval brains of Drosophila nasutoides. Biochem. Genet. 12, 475–483 (1974)
Lee, C.S., Collins, L.: Q- and C-bands in the metaphase chromosomes of Drosophila nasutoides. Chromosoma (Berl.) 61, 57–60 (1977)
Lipschitz, L., Axel, R.: Restriction endonuclease cleavage of satellite DNA in intact Bovine nuclei. Cell 9, 355–364 (1976)
Morris, N.R.: Nucleosome structure in Aspergillus nidulans. Cell 8, 357–363 (1976)
Noll, M.: Internal structure of the chromatin subunit. Nucl. Acids Res. 1, 1573–1578 (1974)
Noll, M.: Differences and similarities in chromatin structure of Neurospora crassa and higher eucaryotes. Cell 8, 349–355 (1976)
Olins, D.E., Olins, A.L.: Spheroid chromatin units (nu-bodies). Science 183, 330–332 (1974)
Shaw, B.R., Herman, T.M., Kovacic, R.T., Beaudreau, G.S., van Holde, K.E.: Analysis of subunit organization in chicken erythrocyte chromatin. Proc. nat. Acad. Sci. (Wash.) 73, 505–509 (1976)
Sollner-Webb, B., Felsenfeld, G.: A comparison of the digestion of nuclei and chromatin by staphylococcal nuclease. Biochemistry 14, 2915–2920 (1975)
Thomas, J.O., Furber, V.: Yeast chromatin structure. FEBS Letters 66, 274–280 (1976)
Thomas, J.O., Thompson, K.J.: Variation in chromatin structure in two cell types from the same tissue: a short DNA repeat length in cerebral cortex neurons. Cell 10, 633–640 (1977)
Weintraub, H., Worcel, A., Alberts, B.: A model for chromatin based upon two symmetrically paired half-nucleosomes. Cell 9, 409–417 (1976)
Wiesehahn, G.P., Hyde, J.E., Hearst, J.E.: Photoaddition of trimethylpsoralen to Drosophila melanogaster nuclei: A probe for chromatin structure. Biochemistry 16, 925–932 (1977)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Lee, C.S. Chromatin structure of Drosophila nasutoides satellites as probed by cross-linking DNA in situ. Chromosoma 65, 103–114 (1978). https://doi.org/10.1007/BF00329463
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00329463