Multiple interactions between RNA polymerase I, TIF‐IA and TAF
            <sub>I</sub>
            subunits regulate preinitiation complex assembly at the ribosomal gene promoter

Yuan, Xuejun; Zhao, Jing; Zentgraf, Hanswalter; Hoffmann-Rohrer, Urs; Grummt, Ingrid

doi:10.1093/embo-reports/kvf212

Cited by 93 publications

(92 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We believe that the primary sequence of the A34.5 homolog, if any such protein exists, may be poorly conserved in S. pombe. Mouse pol I has been found to contain distinct subunits from lower eukaryotes, such as PAF67 and PAF49 (33,34,50). These results tempt us to speculate that lower eukaryotes such as yeast might conserve the 14 subunits found in S. cerevisiae and that higher eukaryotes might have more specific subunits such as PAF67 and PAF49, in addition to the 14 conserved subunits.…”

Section: Discussionmentioning

confidence: 95%

The Fission Yeast Protein Ker1p Is an Ortholog of RNA Polymerase I Subunit A14 in Saccharomyces cerevisiae and Is Required for Stable Association of Rrn3p and RPA21 in RNA Polymerase I

Imazawa

Hisatake

Mitsuzawa

et al. 2005

Journal of Biological Chemistry

View full text Add to dashboard Cite

A heterodimer formed by the A14 and A43 subunits of RNA polymerase (pol) I in Saccharomyces cerevisiae is proposed to correspond to the Rpb4/Rpb7 and C17/C25 heterodimers in pol II and pol III, respectively, and to play a role(s) in the recruitment of pol I to the promoter. However, the question of whether the A14/A43 heterodimer is conserved in eukaryotes other than S. cerevisiae remains unanswered, although both Rpb4/Rpb7 and C17/C25 are conserved from yeast to human. To address this question, we have isolated a Schizosaccharomyces pombe gene named ker1 ؉ using a yeast twohybrid system, including rpa21 ؉ , which encodes an ortholog of A43, as bait. Although no homolog of A14 has previously been found in the S. pombe genome, functional characterization of Ker1p and alignment of Ker1p and A14 showed that Ker1p is an ortholog of A14. Disruption of ker1 ؉ resulted in temperature-sensitive growth, and the temperature-sensitive deficit of ker1⌬ was suppressed by overexpression of either rpa21 ؉ or rrn3 ؉ , which encodes the rDNA transcription factor Rrn3p, suggesting that Ker1p is involved in stabilizing the association of RPA21 and Rrn3p in pol I. We also found that Ker1p dissociated from pol I in post-logphase cells, suggesting that Ker1p is involved in growthdependent regulation of rDNA transcription.There are three distinct types of eukaryotic nuclear RNA polymerases: RNA polymerase (pol) 1 I, pol II, and pol III. Among eukaryotic organisms, the structure and function of RNA polymerases in Saccharomyces cerevisiae have been studied fairly extensively (1-4). S. cerevisiae pol I consists of 14 subunits. The core structure contains 10 subunits (A190, A135, AC40, AC19, Rpb5, Rpb6, Rpb8, Rpb10, Rpb12, and A12.2) and is believed to be sufficient for nonspecific transcription, but not for accurate initiation of transcription (5). In fact, pol I requires four specific subunits (A49, A43, A34.5, and A14) for specific transcription of rDNA. A43 is also essential for cell growth (6), whereas A49 (7), A34.5 (8), and A14 (9) are dispensable.Much attention has recently been focused on the A14 and A43 subunits in view of the structural and functional conservation of these two subunits in eukaryotes. A43 is conserved in a variety of eukaryotes (10) and shows amino acid sequence similarity to Rpb7 (a specific subunit of pol II), C25 (a specific subunit of pol III), and RpoE (a subunit of archaeal RNA polymerases) across multiple RNA polymerases (11). Furthermore, A43 forms a heterodimer with A14 that is similar to the Rpb4/Rpb7 (11, 12), C17/C25 (13), and RpoF/RpoE (14) heterodimers in pol II, pol III, and archaeal RNA polymerases, respectively. It should be noted that Rpb4, C17, and RpoF have mutual sequence similarity and are grouped into a gene family, but no obvious homolog of A14 has been found in available data bases. A14 and Rpb4 are required for the stable assembly of A43 and Rpb7, respectively, in their respective RNA polymerases, suggesting a functional similarity of A14 to Rpb4 (5,11,15,16). The position of A14/A43 in...

show abstract

Section: Discussionmentioning

confidence: 95%

The Fission Yeast Protein Ker1p Is an Ortholog of RNA Polymerase I Subunit A14 in Saccharomyces cerevisiae and Is Required for Stable Association of Rrn3p and RPA21 in RNA Polymerase I

Imazawa

Hisatake

Mitsuzawa

et al. 2005

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…Like Rrn3, human TIF-IA binds A43 (ref. 42), which may be dephosphorylated during the cell cycle by the Cdc14 phosphatase that inhibits Pol I (ref. 43).…”

Section: Article Researchmentioning

confidence: 99%

RNA polymerase I structure and transcription regulation

Engel

Sainsbury

Cheung

et al. 2013

Nature

199

305

View full text Add to dashboard Cite

Transcription of ribosomal RNA by RNA polymerase (Pol) I initiates ribosome biogenesis and regulates eukaryotic cell growth. The crystal structure of Pol I fromthe yeast Saccharomyces cerevisiae at 2.8A˚ resolution reveals all 14 subunits of the 590-kilodalton enzyme, and shows differences to Pol II. An ‘expander’ element occupies the DNA template site and stabilizes an expanded active centre cleft with an unwound bridge helix. A ‘connector’ element invades the cleft of an adjacent polymerase and stabilizes an inactive polymerase dimer. The connector and expander must detach during Pol I activation to enable transcription initiation and cleft contraction by convergent movement of the polymerase ‘core’ and ‘shelf’ modules. Conversion between an inactive expanded and an active contracted polymerase state may generally underlie transcription. Regulatory factors can modulate the core–shelf interface that includes a ‘composite’ active site for RNA chain initiation, elongation, proofreading and termination

show abstract

“…Direct contacts between TIF-IA/Rrn3 and UBF have not been described. Presumably TIF-IA/Rrn3 is recruited to pseudo-NORs by interactions with pol I or SL1 (Miller et al 2001;Yuan et al 2002). Although promoters may contribute to sequestration of the pol I machinery by rDNA in nucleoli, the efficiency of targeting to pseudo-NORs suggests that UBF bound to nonpromoter sequences provides the major contributing factor.…”

Section: Org Downloaded Frommentioning

confidence: 99%

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

Mais¹,

Wright²,

Prieto³

et al. 2004

Genes Dev.

163

191

View full text Add to dashboard Cite

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] Supplemental material is available at http://www.genesdev.org.

show abstract

Multiple interactions between RNA polymerase I, TIF‐IA and TAF _I subunits regulate preinitiation complex assembly at the ribosomal gene promoter

Cited by 93 publications

References 24 publications

The Fission Yeast Protein Ker1p Is an Ortholog of RNA Polymerase I Subunit A14 in Saccharomyces cerevisiae and Is Required for Stable Association of Rrn3p and RPA21 in RNA Polymerase I

The Fission Yeast Protein Ker1p Is an Ortholog of RNA Polymerase I Subunit A14 in Saccharomyces cerevisiae and Is Required for Stable Association of Rrn3p and RPA21 in RNA Polymerase I

RNA polymerase I structure and transcription regulation

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

Contact Info

Product

Resources

About

Multiple interactions between RNA polymerase I, TIF‐IA and TAF I subunits regulate preinitiation complex assembly at the ribosomal gene promoter

Cited by 93 publications

References 24 publications

The Fission Yeast Protein Ker1p Is an Ortholog of RNA Polymerase I Subunit A14 in Saccharomyces cerevisiae and Is Required for Stable Association of Rrn3p and RPA21 in RNA Polymerase I

The Fission Yeast Protein Ker1p Is an Ortholog of RNA Polymerase I Subunit A14 in Saccharomyces cerevisiae and Is Required for Stable Association of Rrn3p and RPA21 in RNA Polymerase I

RNA polymerase I structure and transcription regulation

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

Contact Info

Product

Resources

About

Multiple interactions between RNA polymerase I, TIF‐IA and TAF _I subunits regulate preinitiation complex assembly at the ribosomal gene promoter