Abstract
DNA renaturation kinetics was used to examine the relative accessibility of various regions of the Tetrahymena ribosomal RNA gene (rDNA) chromatin to micrococcal nuclease. In nuclei from cells active in rRNA transcription, the transcribed region of the rDNA chromatin was as much as 5-fold more accessible than the average of the total chromatin. As few as 20% inactive genes in the population could have accounted for all of the hybridization, so the transcribed region of the active units may be totally unprotected from nuclease degradation. The terminal non-transcribed spacer downstream from the transcription unit was also preferentially digested, but to a smaller degree. The central non-transcribed spacer was degraded to the same extent as total chromatin after a high degree of nuclease digestion. In nuclei from starved cells, which have 96% reduced rRNA transcription, the transcribed and terminal spacer regions of the rDNA were again more accessible than the total chromatin from the same nuclei, but the difference did not exceed 2-fold. We conclude that transcriptional activation is accompanied by major changes in the structure of the ribosomal gene chromatin, and that the extent and/or type of structural alteration differs in each functionally defined region of the rDNA.
Full text
PDF














Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bellard M., Gannon F., Chambon P. Nucleosome structure III: the structure and transcriptional activity of the chromatin containing the ovalbumin and globin genes in chick oviduct nuclei. Cold Spring Harb Symp Quant Biol. 1978;42(Pt 2):779–791. doi: 10.1101/sqb.1978.042.01.078. [DOI] [PubMed] [Google Scholar]
- Bloom K. S., Anderson J. N. Fractionation of hen oviduct chromatin into transcriptionally active and inactive regions after selective micrococcal nuclease digestion. Cell. 1978 Sep;15(1):141–150. doi: 10.1016/0092-8674(78)90090-9. [DOI] [PubMed] [Google Scholar]
- Borchsenius S., Bonven B., Leer J. C., Westergaard O. Nuclease-sensitive regions on the extrachromosomal r-chromatin from Tetrahymena pyriformis. Eur J Biochem. 1981 Jul;117(2):245–250. doi: 10.1111/j.1432-1033.1981.tb06329.x. [DOI] [PubMed] [Google Scholar]
- Cech T. R., Brehm S. L. Replication of the extrachromosomal ribosomal RNA genes of Tetrahymena thermophilia. Nucleic Acids Res. 1981 Jul 24;9(14):3531–3543. doi: 10.1093/nar/9.14.3531. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cech T. R., Karrer K. M. Chromatin structure of the ribosomal RNA genes of Tetrahymena thermophila as analyzed by trimethylpsoralen crosslinking in vivo. J Mol Biol. 1980 Feb 5;136(4):395–416. doi: 10.1016/0022-2836(80)90397-6. [DOI] [PubMed] [Google Scholar]
- Dingwall C., Lomonossoff G. P., Laskey R. A. High sequence specificity of micrococcal nuclease. Nucleic Acids Res. 1981 Jun 25;9(12):2659–2673. doi: 10.1093/nar/9.12.2659. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Eckert W. A., Kaffenberger W. Regulation of rRNA metabolism in Tetrahymena pyriformis. I. Nutritional shift-down. Eur J Cell Biol. 1980 Apr;21(1):53–62. [PubMed] [Google Scholar]
- Engberg J., Nasir-ud-Din, Eckert W. A., Kaffenberger W., Pearlman R. E. Detailed transcription map of the extrachromosomal ribosomal RNA genes in Tetrahymena thermophila. J Mol Biol. 1980 Sep 25;142(3):289–313. doi: 10.1016/0022-2836(80)90274-0. [DOI] [PubMed] [Google Scholar]
- Hörz W., Altenburger W. Sequence specific cleavage of DNA by micrococcal nuclease. Nucleic Acids Res. 1981 Jun 25;9(12):2643–2658. doi: 10.1093/nar/9.12.2643. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Johnson E. M., Campbell G. R., Allfrey V. G. Different nucleosome structures on transcribing and nontranscribing ribosomal gene sequences. Science. 1979 Dec 7;206(4423):1192–1194. doi: 10.1126/science.505006. [DOI] [PubMed] [Google Scholar]
- Judelson H. S., Vogt V. M. Accessibility of ribosomal genes to trimethyl psoralen in nuclei of Physarum polycephalum. Mol Cell Biol. 1982 Mar;2(3):211–220. doi: 10.1128/mcb.2.3.211. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kiss G. B., Amin A. A., Pearlman R. E. Two separate regions of the extrachromosomal ribosomal deoxyribonucleic acid of Tetrahymena thermophila enable autonomous replication of plasmids in Saccharomyces cerevisiae. Mol Cell Biol. 1981 Jun;1(6):535–543. doi: 10.1128/mcb.1.6.535. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kiss G. B., Pearlman R. E. Extrachromosomal rDNA of Tetrahymena thermophila is not a perfect palindrome. Gene. 1981 Apr;13(3):281–287. doi: 10.1016/0378-1119(81)90032-9. [DOI] [PubMed] [Google Scholar]
- Levy-Wilson B., Dixon G. H. Limited action of micrococcal nuclease on trout testis nuclei generates two mononucleosome subsets enriched in transcribed DNA sequences. Proc Natl Acad Sci U S A. 1979 Apr;76(4):1682–1686. doi: 10.1073/pnas.76.4.1682. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mathis D. J., Gorovsky M. A. Subunit structure of rDNA-containing chromatin. Biochemistry. 1976 Feb 24;15(4):750–755. doi: 10.1021/bi00649a005. [DOI] [PubMed] [Google Scholar]
- Mathis D., Oudet P., Chambon P. Structure of transcribing chromatin. Prog Nucleic Acid Res Mol Biol. 1980;24:1–55. doi: 10.1016/s0079-6603(08)60670-4. [DOI] [PubMed] [Google Scholar]
- Piper P. W., Celis J., Kaltoft K., Leer J. C., Nielsen O. F., Westergaard O. Tetrahymena ribosomal RNA gene chromatin is digested by micrococcal nuclease at sites which have the same regular spacing on the DNA as corresponding sites in the bulk nuclear chromatin. Nucleic Acids Res. 1976 Feb;3(2):493–505. doi: 10.1093/nar/3.2.493. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Reeves R. Ribosomal genes of Xenopus laevis: evidence of nucleosomes in transcriptionally active chromatin. Science. 1976 Oct 29;194(4264):529–532. doi: 10.1126/science.973136. [DOI] [PubMed] [Google Scholar]
- Reeves R. Structure of Xenopus ribosomal gene chromatin during changes in genomic transcription rates. Cold Spring Harb Symp Quant Biol. 1978;42(Pt 2):709–722. doi: 10.1101/sqb.1978.042.01.073. [DOI] [PubMed] [Google Scholar]
- Stalder J., Seebeck T., Braun R. Accessibility of the ribosomal genes to micrococcal nuclease in Physarum polycephalum. Biochim Biophys Acta. 1979 Feb 27;561(2):452–463. doi: 10.1016/0005-2787(79)90153-9. [DOI] [PubMed] [Google Scholar]
- Sutton C. A., Sylvan P., Hallberg R. L. Ribosome biosynthesis in Tetrahymena thermophila. IV. Regulation of ribosomal RNA synthesis in growing and growth arrested cells. J Cell Physiol. 1979 Dec;101(3):503–513. doi: 10.1002/jcp.1041010316. [DOI] [PubMed] [Google Scholar]
- VONHIPPEL P. H., FELSENFELD G. MICROCOCCAL NUCLEASE AS A PROBE OF DNA CONFORMATION. Biochemistry. 1964 Jan;3:27–39. doi: 10.1021/bi00889a006. [DOI] [PubMed] [Google Scholar]
- Vavra K. J., Pederson D. S., Gorovsky M. A. Nuclease sensitivity of chromatin containing active genes: kinetic analyses utilizing continuous elution of digestion products from an ultrafiltration cell. Nucleic Acids Res. 1981 Nov 11;9(21):5825–5843. doi: 10.1093/nar/9.21.5825. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wetmur J. G., Davidson N. Kinetics of renaturation of DNA. J Mol Biol. 1968 Feb 14;31(3):349–370. doi: 10.1016/0022-2836(68)90414-2. [DOI] [PubMed] [Google Scholar]
- Wu C. The 5' ends of Drosophila heat shock genes in chromatin are hypersensitive to DNase I. Nature. 1980 Aug 28;286(5776):854–860. doi: 10.1038/286854a0. [DOI] [PubMed] [Google Scholar]
- Wu C., Wong Y. C., Elgin S. C. The chromatin structure of specific genes: II. Disruption of chromatin structure during gene activity. Cell. 1979 Apr;16(4):807–814. doi: 10.1016/0092-8674(79)90096-5. [DOI] [PubMed] [Google Scholar]
- Yao M. C., Gorovsky M. A. Comparison of the sequences of macro- and micronuclear DNA of Tetrahymena pyriformis. Chromosoma. 1974;48(1):1–18. doi: 10.1007/BF00284863. [DOI] [PubMed] [Google Scholar]


