Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Genes Dev
2005 Jan 01;191:50-64. doi: 10.1101/gad.310705.
Show Gene links
Show Anatomy links
UBF-binding site arrays form pseudo-NORs and sequester the RNA polymerase I transcription machinery.
Mais C
,
Wright JE
,
Prieto JL
,
Raggett SL
,
McStay B
.
???displayArticle.abstract???
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.
???displayArticle.pubmedLink???
15598984
???displayArticle.pmcLink???PMC540225 ???displayArticle.link???Genes Dev
Aprikian,
New model for the yeast RNA polymerase I transcription cycle.
2001, Pubmed
Aprikian,
New model for the yeast RNA polymerase I transcription cycle.
2001,
Pubmed
Bazett-Jones,
Short-range DNA looping by the Xenopus HMG-box transcription factor, xUBF.
1994,
Pubmed
,
Xenbase
Beckmann,
Coactivator and promoter-selective properties of RNA polymerase I TAFs.
1995,
Pubmed
Bell,
Functional cooperativity between transcription factors UBF1 and SL1 mediates human ribosomal RNA synthesis.
1988,
Pubmed
Bell,
Molecular mechanisms governing species-specific transcription of ribosomal RNA.
1989,
Pubmed
,
Xenbase
Bodem,
TIF-IA, the factor mediating growth-dependent control of ribosomal RNA synthesis, is the mammalian homolog of yeast Rrn3p.
2000,
Pubmed
Chubb,
Chromatin motion is constrained by association with nuclear compartments in human cells.
2002,
Pubmed
Comai,
The TATA-binding protein and associated factors are integral components of the RNA polymerase I transcription factor, SL1.
1992,
Pubmed
Dundr,
A kinetic framework for a mammalian RNA polymerase in vivo.
2002,
Pubmed
Gadal,
Hmo1, an HMG-box protein, belongs to the yeast ribosomal DNA transcription system.
2002,
Pubmed
Goodpasture,
Visualization of nucleolar organizer regions im mammalian chromosomes using silver staining.
1975,
Pubmed
Grummt,
Life on a planet of its own: regulation of RNA polymerase I transcription in the nucleolus.
2003,
Pubmed
Hanada,
RNA polymerase I associated factor 53 binds to the nucleolar transcription factor UBF and functions in specific rDNA transcription.
1996,
Pubmed
Heix,
Species specificity of transcription by RNA polymerase I.
1995,
Pubmed
Heliot,
Electron tomography of metaphase nucleolar organizer regions: evidence for a twisted-loop organization.
1997,
Pubmed
Henderson,
Location of ribosomal DNA in the human chromosome complement.
1972,
Pubmed
Kermekchiev,
Nucleosome binding by the polymerase I transactivator upstream binding factor displaces linker histone H1.
1997,
Pubmed
,
Xenbase
Kuhn,
A 140-base-pair repetitive sequence element in the mouse rRNA gene spacer enhances transcription by RNA polymerase I in a cell-free system.
1990,
Pubmed
,
Xenbase
Kuhn,
Functional differences between the two splice variants of the nucleolar transcription factor UBF: the second HMG box determines specificity of DNA binding and transcriptional activity.
1994,
Pubmed
Kwon,
The RNA polymerase I transcription factor, upstream binding factor, interacts directly with the TATA box-binding protein.
1994,
Pubmed
Labhart,
Enhancer-like properties of the 60/81 bp elements in the ribosomal gene spacer of Xenopus laevis.
1984,
Pubmed
,
Xenbase
Längst,
TTF-I determines the chromatin architecture of the active rDNA promoter.
1998,
Pubmed
Längst,
RNA polymerase I transcription on nucleosomal templates: the transcription termination factor TTF-I induces chromatin remodeling and relieves transcriptional repression.
1997,
Pubmed
Maeda,
Mouse rRNA gene transcription factor mUBF requires both HMG-box1 and an acidic tail for nucleolar accumulation: molecular analysis of the nucleolar targeting mechanism.
1992,
Pubmed
McStay,
An RNA polymerase I termination site can stimulate the adjacent ribosomal gene promoter by two distinct mechanisms in Xenopus laevis.
1990,
Pubmed
,
Xenbase
McStay,
The Xenopus RNA polymerase I transcription factor, UBF, has a role in transcriptional enhancement distinct from that at the promoter.
1997,
Pubmed
,
Xenbase
Miller,
hRRN3 is essential in the SL1-mediated recruitment of RNA Polymerase I to rRNA gene promoters.
2001,
Pubmed
Miller,
Morphological studies of transcription.
1972,
Pubmed
Moss,
At the center of eukaryotic life.
2002,
Pubmed
O'Mahony,
Identification of two forms of the RNA polymerase I transcription factor UBF.
1991,
Pubmed
O'Sullivan,
UBF binding in vivo is not restricted to regulatory sequences within the vertebrate ribosomal DNA repeat.
2002,
Pubmed
,
Xenbase
Paule,
Survey and summary: transcription by RNA polymerases I and III.
2000,
Pubmed
Pikaard,
The Xenopus ribosomal gene enhancers bind an essential polymerase I transcription factor, xUBF.
1989,
Pubmed
,
Xenbase
Putnam,
Cooperative binding of the Xenopus RNA polymerase I transcription factor xUBF to repetitive ribosomal gene enhancers.
1992,
Pubmed
,
Xenbase
Puvion-Dutilleul,
Morphology of transcription at cellular and molecular levels.
1983,
Pubmed
Pérez-Castillo,
New insights into the effects of extra nucleolus organizer regions.
1986,
Pubmed
Roussel,
Localization of the RNA polymerase I transcription factor hUBF during the cell cycle.
1993,
Pubmed
Roussel,
Identification of Ag-NOR proteins, markers of proliferation related to ribosomal gene activity.
1994,
Pubmed
Roussel,
The rDNA transcription machinery is assembled during mitosis in active NORs and absent in inactive NORs.
1996,
Pubmed
Sakai,
Human ribosomal RNA gene cluster: identification of the proximal end containing a novel tandem repeat sequence.
1995,
Pubmed
Santoro,
The nucleolar remodeling complex NoRC mediates heterochromatin formation and silencing of ribosomal gene transcription.
2002,
Pubmed
Scheer,
Functional and dynamic aspects of the mammalian nucleolus.
1990,
Pubmed
Simpson,
Systematic subcellular localization of novel proteins identified by large-scale cDNA sequencing.
2000,
Pubmed
Strukov,
Engineered chromosome regions with altered sequence composition demonstrate hierarchical large-scale folding within metaphase chromosomes.
2003,
Pubmed
Sullivan,
Human acrocentric chromosomes with transcriptionally silent nucleolar organizer regions associate with nucleoli.
2001,
Pubmed
Sumner,
The nature and mechanisms of chromosome banding.
1982,
Pubmed
Thomas,
HMG1 and 2, and related 'architectural' DNA-binding proteins.
2001,
Pubmed
Weisenberger,
A possible mechanism for the inhibition of ribosomal RNA gene transcription during mitosis.
1995,
Pubmed
Yuan,
Multiple interactions between RNA polymerase I, TIF-IA and TAF(I) subunits regulate preinitiation complex assembly at the ribosomal gene promoter.
2002,
Pubmed
