QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Supplemental Research Data All Versions of this Article: gad.310705v1 19/1/50    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Mais, C. Articles by McStay, B. Search for Related Content PubMed PubMed Citation Articles by Mais, C. Articles by McStay, B. Social Bookmarking                   What's this?

RESEARCH PAPER

UBF-binding site arrays form pseudo-NORs and sequester the RNA polymerase I transcription machinery

Biomedical Research Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY Scotland, United Kingdom

Human ribosomal genes (rDNA) are located in nucleolar organizer regions (NORs) on the short arms of acrocentric chromosomes. Metaphase NORs that were transcriptionally active in the previous cell cycle appear as prominent chromosomal features termed secondary constrictions that are achromatic in chromosome banding and positive in silver staining. The architectural RNA polymerase I (pol I) transcription factor UBF binds extensively across rDNA throughout the cell cycle. To determine if UBF binding underpins NOR structure, we integrated large arrays of heterologous UBF-binding sequences at ectopic sites on human chromosomes. These arrays efficiently recruit UBF even to sites outside the nucleolus and, during metaphase, form novel silver stainable secondary constrictions, termed pseudo-NORs, morphologically similar to NORs. We demonstrate for the first time that in addition to UBF the other components of the pol I machinery are found associated with sequences across the entire human rDNA repeat. Remarkably, a significant fraction of these same pol I factors are sequestered by pseudo-NORs independent of both transcription and nucleoli. Because of the heterologous nature of the sequence employed, we infer that sequestration is mediated primarily by protein–protein interactions with UBF. These results suggest that extensive binding of UBF is responsible for formation and maintenance of the secondary constriction at active NORs. Furthermore, we propose that UBF mediates recruitment of the pol I machinery to nucleoli independently of promoter elements.

[Keywords: RNA polymerase I; ribosomal DNA; nucleolar organiser region; nucleolus; upstream-binding factor]

Received May 24, 2004; revised version accepted October 19, 2004.

Article published online ahead of print. Article and publication date are at http://www.genesdev.org/cgi/doi/10.1101/gad.310705.

¹ These authors contributed equally to this work.

² Corresponding author.

E-MAIL: brian.mcstay{at}cancer.org.uk; FAX 01382-669993.

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				M. Xu and P. R. Cook Similar active genes cluster in specialized transcription factories J. Cell Biol., May 19, 2008; 181(4): 615 - 623. [Abstract] [Full Text] [PDF]

				K. Kasahara, K. Ohtsuki, S. Ki, K. Aoyama, H. Takahashi, T. Kobayashi, K. Shirahige, and T. Kokubo Assembly of Regulatory Factors on rRNA and Ribosomal Protein Genes in Saccharomyces cerevisiae Mol. Cell. Biol., October 1, 2007; 27(19): 6686 - 6705. [Abstract] [Full Text] [PDF]

				J.-L. Prieto and B. McStay Recruitment of factors linking transcription and processing of pre-rRNA to NOR chromatin is UBF-dependent and occurs independent of transcription in human cells Genes & Dev., August 15, 2007; 21(16): 2041 - 2054. [Abstract] [Full Text] [PDF]

				A. R.D. Ganley and T. Kobayashi Highly efficient concerted evolution in the ribosomal DNA repeats: Total rDNA repeat variation revealed by whole-genome shotgun sequence data Genome Res., February 1, 2007; 17(2): 184 - 191. [Abstract] [Full Text] [PDF]

				K. Kopp, J. Z. Gasiorowski, D. Chen, R. Gilmore, J. T. Norton, C. Wang, D. J. Leary, E.K.L. Chan, D. A. Dean, and S. Huang Pol I Transcription and Pre-rRNA Processing Are Coordinated in a Transcription-dependent Manner in Mammalian Cells Mol. Biol. Cell, February 1, 2007; 18(2): 394 - 403. [Abstract] [Full Text] [PDF]

				C.-Y. Lin, S. Navarro, S. Reddy, and L. Comai CK2-mediated stimulation of Pol I transcription by stabilization of UBF-SL1 interaction Nucleic Acids Res., October 18, 2006; 34(17): 4752 - 4766. [Abstract] [Full Text] [PDF]

				F. J. Lawrence, B. McStay, and D. A. Matthews Nucleolar protein upstream binding factor is sequestered into adenovirus DNA replication centres during infection without affecting RNA polymerase I location or ablating rRNA synthesis J. Cell Sci., June 15, 2006; 119(12): 2621 - 2631. [Abstract] [Full Text] [PDF]

				A. von Mikecz The nuclear ubiquitin-proteasome system J. Cell Sci., May 15, 2006; 119(10): 1977 - 1984. [Abstract] [Full Text] [PDF]

				B. McStay Nucleolar dominance: a model for rRNA gene silencing. Genes & Dev., May 15, 2006; 20(10): 1207 - 1214. [Full Text] [PDF]

				J. Meraner, M. Lechner, A. Loidl, M. Goralik-Schramel, R. Voit, I. Grummt, and P. Loidl Acetylation of UBF changes during the cell cycle and regulates the interaction of UBF with RNA polymerase I. Nucleic Acids Res., January 1, 2006; 34(6): 1798 - 1806. [Abstract] [Full Text] [PDF]

				J. K. Friedrich, K. I. Panov, P. Cabart, J. Russell, and J. C. B. M. Zomerdijk TBP-TAF Complex SL1 Directs RNA Polymerase I Pre-initiation Complex Formation and Stabilizes Upstream Binding Factor at the rDNA Promoter J. Biol. Chem., August 19, 2005; 280(33): 29551 - 29558. [Abstract] [Full Text] [PDF]