Abstract
DNA-dependent protein kinase (DNA-PK) is a nuclear enzyme that phosphorylates several transcription factors, but its cellular function has not been elucidated. Here I show that DNA-PK strongly inhibits promoter-directed transcription initiation by Xenopus RNA polymerase I in vitro. The repression is due to protein phosphorylation, since it is relieved by 6-dimethylaminopurine, an inhibitor of protein kinases. DNA-PK inhibits transcription from both linear and circular templates, but the repression is more efficient on linear templates. DNA-PK has no effect on promoter-directed transcription by RNA polymerases II and III. Partial fractionation of the in vitro transcription system shows that a protein fraction containing transcription factor Rib1, the Xenopus equivalent of human SL1, mediates the repression of transcription by DNA-PK. The present data suggest a role for DNA-PK in down-regulating ribosomal gene transcription.
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- Anderson C. W., Lees-Miller S. P. The nuclear serine/threonine protein kinase DNA-PK. Crit Rev Eukaryot Gene Expr. 1992;2(4):283–314. [PubMed] [Google Scholar]
- Arias J. A., Peterson S. R., Dynan W. S. Promoter-dependent phosphorylation of RNA polymerase II by a template-bound kinase. Association with transcriptional initiation. J Biol Chem. 1991 May 5;266(13):8055–8061. [PubMed] [Google Scholar]
- Carter T., Vancurová I., Sun I., Lou W., DeLeon S. A DNA-activated protein kinase from HeLa cell nuclei. Mol Cell Biol. 1990 Dec;10(12):6460–6471. doi: 10.1128/mcb.10.12.6460. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Comai L., Tanese N., Tjian R. The TATA-binding protein and associated factors are integral components of the RNA polymerase I transcription factor, SL1. Cell. 1992 Mar 6;68(5):965–976. doi: 10.1016/0092-8674(92)90039-f. [DOI] [PubMed] [Google Scholar]
- 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]
- Dvir A., Stein L. Y., Calore B. L., Dynan W. S. Purification and characterization of a template-associated protein kinase that phosphorylates RNA polymerase II. J Biol Chem. 1993 May 15;268(14):10440–10447. [PubMed] [Google Scholar]
- Eberhard D., Tora L., Egly J. M., Grummt I. A TBP-containing multiprotein complex (TIF-IB) mediates transcription specificity of murine RNA polymerase I. Nucleic Acids Res. 1993 Sep 11;21(18):4180–4186. doi: 10.1093/nar/21.18.4180. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Falzon M., Fewell J. W., Kuff E. L. EBP-80, a transcription factor closely resembling the human autoantigen Ku, recognizes single- to double-strand transitions in DNA. J Biol Chem. 1993 May 15;268(14):10546–10552. [PubMed] [Google Scholar]
- Finnie N., Gottlieb T., Hartley K., Jackson S. P. Transcription factor phosphorylation by the DNA-dependent protein kinase. Biochem Soc Trans. 1993 Nov;21(4):930–935. doi: 10.1042/bst0210930. [DOI] [PubMed] [Google Scholar]
- 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]
- Griffith A. J., Blier P. R., Mimori T., Hardin J. A. Ku polypeptides synthesized in vitro assemble into complexes which recognize ends of double-stranded DNA. J Biol Chem. 1992 Jan 5;267(1):331–338. [PubMed] [Google Scholar]
- Jackson S. P., MacDonald J. J., Lees-Miller S., Tjian R. GC box binding induces phosphorylation of Sp1 by a DNA-dependent protein kinase. Cell. 1990 Oct 5;63(1):155–165. doi: 10.1016/0092-8674(90)90296-q. [DOI] [PubMed] [Google Scholar]
- Kermekchiev M., Muramatsu M. Presence of an inhibitor of RNA polymerase I mediated transcription in extracts from growth arrested mouse cells. Nucleic Acids Res. 1993 Feb 11;21(3):447–453. doi: 10.1093/nar/21.3.447. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Konno-Sato S., Wu J. M., Carter T. H. Phosphorylation of a 72-kDa nucleoprotein (NP-72) in HL-60 cells is mediated by the double-stranded DNA-dependent protein kinase (DNA-PK). Biochem Mol Biol Int. 1993 Sep;31(1):113–124. [PubMed] [Google Scholar]
- Kuhn A., Stefanovsky V., Grummt I. The nucleolar transcription activator UBF relieves Ku antigen-mediated repression of mouse ribosomal gene transcription. Nucleic Acids Res. 1993 May 11;21(9):2057–2063. doi: 10.1093/nar/21.9.2057. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Labhart P. Identification of two steps during Xenopus ribosomal gene transcription that are sensitive to protein phosphorylation. Mol Cell Biol. 1994 Mar;14(3):2011–2020. doi: 10.1128/mcb.14.3.2011. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Labhart P., Reeder R. H. A point mutation uncouples RNA 3'-end formation and termination during ribosomal gene transcription in Xenopus laevis. Genes Dev. 1990 Feb;4(2):269–276. doi: 10.1101/gad.4.2.269. [DOI] [PubMed] [Google Scholar]
- Labhart P., Reeder R. H. Xenopus ribosomal gene enhancers function when inserted inside the gene they enhance. Nucleic Acids Res. 1985 Dec 20;13(24):8999–9009. doi: 10.1093/nar/13.24.8999. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 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]
- Lees-Miller S. P., Chen Y. R., Anderson C. W. Human cells contain a DNA-activated protein kinase that phosphorylates simian virus 40 T antigen, mouse p53, and the human Ku autoantigen. Mol Cell Biol. 1990 Dec;10(12):6472–6481. doi: 10.1128/mcb.10.12.6472. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McKnight S. L., Gavis E. R., Kingsbury R., Axel R. Analysis of transcriptional regulatory signals of the HSV thymidine kinase gene: identification of an upstream control region. Cell. 1981 Aug;25(2):385–398. doi: 10.1016/0092-8674(81)90057-x. [DOI] [PubMed] [Google Scholar]
- McKnight S. L. The nucleotide sequence and transcript map of the herpes simplex virus thymidine kinase gene. Nucleic Acids Res. 1980 Dec 20;8(24):5949–5964. doi: 10.1093/nar/8.24.5949. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 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]
- McStay B., Reeder R. H. A DNA-binding protein is required for termination of transcription by RNA polymerase I in Xenopus laevis. Mol Cell Biol. 1990 Jun;10(6):2793–2800. doi: 10.1128/mcb.10.6.2793. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McStay B., Reeder R. H. A termination site for Xenopus RNA polymerase I also acts as an element of an adjacent promoter. Cell. 1986 Dec 26;47(6):913–920. doi: 10.1016/0092-8674(86)90806-8. [DOI] [PubMed] [Google Scholar]
- Morozov V. E., Falzon M., Anderson C. W., Kuff E. L. DNA-dependent protein kinase is activated by nicks and larger single-stranded gaps. J Biol Chem. 1994 Jun 17;269(24):16684–16688. [PubMed] [Google Scholar]
- Neant I., Guerrier P. 6-Dimethylaminopurine blocks starfish oocyte maturation by inhibiting a relevant protein kinase activity. Exp Cell Res. 1988 May;176(1):68–79. doi: 10.1016/0014-4827(88)90121-8. [DOI] [PubMed] [Google Scholar]
- O'Mahony D. J., Xie W. Q., Smith S. D., Singer H. A., Rothblum L. I. Differential phosphorylation and localization of the transcription factor UBF in vivo in response to serum deprivation. In vitro dephosphorylation of UBF reduces its transactivation properties. J Biol Chem. 1992 Jan 5;267(1):35–38. [PubMed] [Google Scholar]
- Peterson R. C., Doering J. L., Brown D. D. Characterization of two xenopus somatic 5S DNAs and one minor oocyte-specific 5S DNA. Cell. 1980 May;20(1):131–141. doi: 10.1016/0092-8674(80)90241-x. [DOI] [PubMed] [Google Scholar]
- Sollner-Webb B., Reeder R. H. The nucleotide sequence of the initiation and termination sites for ribosomal RNA transcription in X. laevis. Cell. 1979 Oct;18(2):485–499. doi: 10.1016/0092-8674(79)90066-7. [DOI] [PubMed] [Google Scholar]
- Sollner-Webb B., Tower J. Transcription of cloned eukaryotic ribosomal RNA genes. Annu Rev Biochem. 1986;55:801–830. doi: 10.1146/annurev.bi.55.070186.004101. [DOI] [PubMed] [Google Scholar]
- 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]