Skip to main content
PMC home page
Nucleic Acids Research logoLink to Nucleic Acids Research
. 1993 May 11;21(9):2057–2063. doi: 10.1093/nar/21.9.2057

The nucleolar transcription activator UBF relieves Ku antigen-mediated repression of mouse ribosomal gene transcription.

A Kuhn 1, V Stefanovsky 1, I Grummt 1
PMCID: PMC309465  PMID: 8502546

Abstract

Previously we have shown that the RNA polymerase I (Pol I)-specific transcription factor UBF stimulates transcription by both facilitating transcription complex formation and by relieving repression exerted by a negative-acting factor which competes for binding of the murine factor TIF-IB to the ribosomal gene promoter (1). We have purified and functionally characterized this repressor protein from Ehrlich ascites cells. The final preparation contained two polypeptides with molecular masses of 75 and 90 kDa, respectively. Both polypeptides interact with the rDNA promoter as revealed by UV-crosslinking experiments. The specificity of binding to the ribosomal gene promoter was demonstrated in an electrophoretic mobility shift assay and by DNase footprinting. The biochemical properties of this negative-acting factor closely resemble those of the Ku antigen, a human nuclear DNA-binding heterodimer which is the target of autoantibodies in several autoimmune diseases. Anti-Ku antibodies precipitate the repressor activity and overcome transcription inhibition. The data demonstrate that regulation of Pol I gene transcription may involve an antirepression mechanism as already documented for Pol II genes and suggest that Ku protein may be causally involved in repressor-mediated down regulation of rRNA synthesis.

Full text

PDF
2057

Images in this article

2059Image
on p.2059
2059Image
on p.2059
2060Image
on p.2060
2060Image
on p.2060
2061Image
on p.2061
2061Image
on p.2061
2061Image
on p.2061

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bell S. P., Jantzen H. M., Tjian R. Assembly of alternative multiprotein complexes directs rRNA promoter selectivity. Genes Dev. 1990 Jun;4(6):943–954. doi: 10.1101/gad.4.6.943. [DOI] [PubMed] [Google Scholar]
  2. Bell S. P., Learned R. M., Jantzen H. M., Tjian R. Functional cooperativity between transcription factors UBF1 and SL1 mediates human ribosomal RNA synthesis. Science. 1988 Sep 2;241(4870):1192–1197. doi: 10.1126/science.3413483. [DOI] [PubMed] [Google Scholar]
  3. Clos J., Buttgereit D., Grummt I. A purified transcription factor (TIF-IB) binds to essential sequences of the mouse rDNA promoter. Proc Natl Acad Sci U S A. 1986 Feb;83(3):604–608. doi: 10.1073/pnas.83.3.604. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Clos J., Normann A., Ohrlein A., Grummt I. The core promoter of mouse rDNA consists of two functionally distinct domains. Nucleic Acids Res. 1986 Oct 10;14(19):7581–7595. doi: 10.1093/nar/14.19.7581. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Dvir A., Peterson S. R., Knuth M. W., Lu H., Dynan W. S. Ku autoantigen is the regulatory component of a template-associated protein kinase that phosphorylates RNA polymerase II. Proc Natl Acad Sci U S A. 1992 Dec 15;89(24):11920–11924. doi: 10.1073/pnas.89.24.11920. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Felsenfeld G. Chromatin as an essential part of the transcriptional mechanism. Nature. 1992 Jan 16;355(6357):219–224. doi: 10.1038/355219a0. [DOI] [PubMed] [Google Scholar]
  7. Francoeur A. M., Peebles C. L., Gompper P. T., Tan E. M. Identification of Ki (Ku, p70/p80) autoantigens and analysis of anti-Ki autoantibody reactivity. J Immunol. 1986 Mar 1;136(5):1648–1653. [PubMed] [Google Scholar]
  8. Gottlieb T. M., Jackson S. P. The DNA-dependent protein kinase: requirement for DNA ends and association with Ku antigen. Cell. 1993 Jan 15;72(1):131–142. doi: 10.1016/0092-8674(93)90057-w. [DOI] [PubMed] [Google Scholar]
  9. Grummt I., Kuhn A., Bartsch I., Rosenbauer H. A transcription terminator located upstream of the mouse rDNA initiation site affects rRNA synthesis. Cell. 1986 Dec 26;47(6):901–911. doi: 10.1016/0092-8674(86)90805-6. [DOI] [PubMed] [Google Scholar]
  10. Gunderson S. I., Knuth M. W., Burgess R. R. The human U1 snRNA promoter correctly initiates transcription in vitro and is activated by PSE1. Genes Dev. 1990 Dec;4(12A):2048–2060. doi: 10.1101/gad.4.12a.2048. [DOI] [PubMed] [Google Scholar]
  11. Higashiura M., Shimizu Y., Tanimoto M., Morita T., Yagura T. Immunolocalization of Ku-proteins (p80/p70): localization of p70 to nucleoli and periphery of both interphase nuclei and metaphase chromosomes. Exp Cell Res. 1992 Aug;201(2):444–451. doi: 10.1016/0014-4827(92)90293-h. [DOI] [PubMed] [Google Scholar]
  12. Jantzen H. M., Admon A., Bell S. P., Tjian R. Nucleolar transcription factor hUBF contains a DNA-binding motif with homology to HMG proteins. Nature. 1990 Apr 26;344(6269):830–836. doi: 10.1038/344830a0. [DOI] [PubMed] [Google Scholar]
  13. Jantzen H. M., Chow A. M., King D. S., Tjian R. Multiple domains of the RNA polymerase I activator hUBF interact with the TATA-binding protein complex hSL1 to mediate transcription. Genes Dev. 1992 Oct;6(10):1950–1963. doi: 10.1101/gad.6.10.1950. [DOI] [PubMed] [Google Scholar]
  14. Knuth M. W., Gunderson S. I., Thompson N. E., Strasheim L. A., Burgess R. R. Purification and characterization of proximal sequence element-binding protein 1, a transcription activating protein related to Ku and TREF that binds the proximal sequence element of the human U1 promoter. J Biol Chem. 1990 Oct 15;265(29):17911–17920. [PubMed] [Google Scholar]
  15. Kuhn A., Grummt I. Dual role of the nucleolar transcription factor UBF: trans-activator and antirepressor. Proc Natl Acad Sci U S A. 1992 Aug 15;89(16):7340–7344. doi: 10.1073/pnas.89.16.7340. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Learned R. M., Cordes S., Tjian R. Purification and characterization of a transcription factor that confers promoter specificity to human RNA polymerase I. Mol Cell Biol. 1985 Jun;5(6):1358–1369. doi: 10.1128/mcb.5.6.1358. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Learned R. M., Learned T. K., Haltiner M. M., Tjian R. T. Human rRNA transcription is modulated by the coordinate binding of two factors to an upstream control element. Cell. 1986 Jun 20;45(6):847–857. doi: 10.1016/0092-8674(86)90559-3. [DOI] [PubMed] [Google Scholar]
  18. McStay B., Hu C. H., Pikaard C. S., Reeder R. H. xUBF and Rib 1 are both required for formation of a stable polymerase I promoter complex in X. laevis. EMBO J. 1991 Aug;10(8):2297–2303. doi: 10.1002/j.1460-2075.1991.tb07766.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Mimori T., Hardin J. A., Steitz J. A. Characterization of the DNA-binding protein antigen Ku recognized by autoantibodies from patients with rheumatic disorders. J Biol Chem. 1986 Feb 15;261(5):2274–2278. [PubMed] [Google Scholar]
  20. Mishima Y., Financsek I., Kominami R., Muramatsu M. Fractionation and reconstitution of factors required for accurate transcription of mammalian ribosomal RNA genes: identification of a species-dependent initiation factor. Nucleic Acids Res. 1982 Nov 11;10(21):6659–6670. doi: 10.1093/nar/10.21.6659. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. O'Mahony D. J., Smith S. D., Xie W., Rothblum L. I. Analysis of the phosphorylation, DNA-binding and dimerization properties of the RNA polymerase I transcription factors UBF1 and UBF2. Nucleic Acids Res. 1992 Mar 25;20(6):1301–1308. doi: 10.1093/nar/20.6.1301. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Porges A. J., Ng T., Reeves W. H. Antigenic determinants of the Ku (p70/p80) autoantigen are poorly conserved between species. J Immunol. 1990 Dec 15;145(12):4222–4228. [PubMed] [Google Scholar]
  23. Roberts M. R., Miskimins W. K., Ruddle F. H. Nuclear proteins TREF1 and TREF2 bind to the transcriptional control element of the transferrin receptor gene and appear to be associated as a heterodimer. Cell Regul. 1989 Nov;1(1):151–164. doi: 10.1091/mbc.1.1.151. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Schnapp A., Clos J., Hädelt W., Schreck R., Cvekl A., Grummt I. Isolation and functional characterization of TIF-IB, a factor that confers promoter specificity to mouse RNA polymerase I. Nucleic Acids Res. 1990 Mar 25;18(6):1385–1393. doi: 10.1093/nar/18.6.1385. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Tower J., Culotta V. C., Sollner-Webb B. Factors and nucleotide sequences that direct ribosomal DNA transcription and their relationship to the stable transcription complex. Mol Cell Biol. 1986 Oct;6(10):3451–3462. doi: 10.1128/mcb.6.10.3451. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Voit R., Schnapp A., Kuhn A., Rosenbauer H., Hirschmann P., Stunnenberg H. G., Grummt I. The nucleolar transcription factor mUBF is phosphorylated by casein kinase II in the C-terminal hyperacidic tail which is essential for transactivation. EMBO J. 1992 Jun;11(6):2211–2218. doi: 10.1002/j.1460-2075.1992.tb05280.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Yaneva M., Jhiang S. Expression of the Ku protein during cell proliferation. Biochim Biophys Acta. 1991 Oct 8;1090(2):181–187. doi: 10.1016/0167-4781(91)90099-8. [DOI] [PubMed] [Google Scholar]
  28. Yaneva M., Ochs R., McRorie D. K., Zweig S., Busch H. Purification of an 86-70 kDa nuclear DNA-associated protein complex. Biochim Biophys Acta. 1985 Jul 26;841(1):22–29. doi: 10.1016/0304-4165(85)90270-3. [DOI] [PubMed] [Google Scholar]

Articles from Nucleic Acids Research are provided here courtesy of Oxford University Press

RESOURCES