Polymerase I Transcription

Sáez‐Vasquez, Julio; Echeverrı́a, Manuel

doi:10.1002/9781119312994.apr0302

Cited by 4 publications

(6 citation statements)

References 142 publications

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“…Plant genomes contain hundreds to thousands of 45S rRNA genes, which are generally organized in a manner similar to the rDNA arrays of other organisms (Saez-Vasquez and Echeverria, 2006).…”

Section: S Rdna Organizationmentioning

confidence: 99%

“…Little is known about the GTFs and/or accessory factors required for RNA Pol I transcription initiation, elongation, or termination in plants (reviewed in Saez-Vasquez and Echeverria, 2006). However, the TFIIB-related protein, pBrp, is a plant-specific GTF for RNA Pol I. pBrp does not interact with the rDNA promoter but forms a stable ternary complex with Arabidopsis TATA BINDING PROTEIN2 and the rDNA promoter (Imamura et al, 2008).…”

Section: Transcription Of 45s Rrna Genesmentioning

confidence: 99%

“…The 5S rRNA is encoded by transcriptionally separated 5S rDNA units. 45S, 47S, and 35S rDNA are transcribed by RNA polymerase I (Pol I) in a process requiring a large number of general transcription factors (GTFs; Russell and Zomerdijk, 2005;Saez-Vasquez and Echeverria, 2006;Schneider, 2012;Goodfellow and Zomerdijk, 2013). The resulting rRNA precursor transcripts (pre-rRNAs) are processed by numerous ribonucleoprotein (RNP) factors to obtain mature 18S, 5.8S, and 25S/28S rRNAs (Fromont-Racine et al, 2003;Dez and Tollervey, 2004;Chédin et al, 2007;Ebersberger et al, 2014;Weis et al, 2015a).…”

Section: Introductionmentioning

confidence: 99%

“…rDNA transcription, pre-rRNA processing, and ribosome biogenesis have been studied for many years in plants. Initially, most of these studies addressed questions concerning rDNA organization in different plant species, including maize (Zea mays), common wheat (Triticum aestivum), rice (Oryza sativa), radish (Raphanus sativus), Brassica oleracea and Brassica rapa, Arabidopsis (Arabidopsis thaliana), tobacco (Nicotiana tabacum), and potato (Solanum tuberosum; reviewed in Saez- Vasquez and Echeverria, 2006). Later, analysis of the Arabidopsis genome allowed the identification of all ribosomal proteins from the small and large ribosome subunits (Cooke et al, 1997;Barakat et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

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Ribosome Biogenesis in Plants: From Functional 45S Ribosomal DNA Organization to Ribosome Assembly Factors

2019

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The transcription of 18S, 5.8S, and 18S rRNA genes (45S rDNA), cotranscriptional processing of pre-rRNA, and assembly of mature rRNA with ribosomal proteins are the linchpins of ribosome biogenesis. In yeast (Saccharomyces cerevisiae) and animal cells, hundreds of pre-rRNA processing factors have been identified and their involvement in ribosome assembly determined. These studies, together with structural analyses, have yielded comprehensive models of the pre-40S and pre-60S ribosome subunits as well as the largest cotranscriptionally assembled preribosome particle: the 90S/small subunit processome. Here, we present the current knowledge of the functional organization of 45S rDNA, pre-rRNA transcription, rRNA processing activities, and ribosome assembly factors in plants, focusing on data from Arabidopsis (Arabidopsis thaliana). Based on yeast and mammalian cell studies, we describe the ribonucleoprotein complexes and RNA-associated activities and discuss how they might specifically affect the production of 40S and 60S subunits. Finally, we review recent findings concerning pre-rRNA processing pathways and a novel mechanism involved in a ribosome stress response in plants

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“…Plant genomes contain hundreds to thousands of 45S rRNA genes, which are generally organized in a manner similar to the rDNA arrays of other organisms (Saez-Vasquez and Echeverria, 2006).…”

Section: S Rdna Organizationmentioning

confidence: 99%

Section: Transcription Of 45s Rrna Genesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ribosome Biogenesis in Plants: From Functional 45S Ribosomal DNA Organization to Ribosome Assembly Factors

2019

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“…In parallel, RNA polymerase I mediated synthesis of a polycistronic rRNA transcript, the precursor of 18S, 5.8S and 25S rRNA ( Figure 1 Step 1B), from highly duplicated 45S rDNA genomic repeats ( Sáez-Vásquez and Echeverría, 2007 ). The tandem-repeated units are arranged into nucleolar organizer regions (NORs) on the short arms of chromosomes 2 and 4 of Arabidopsis thaliana ( Copenhaver and Pikaard, 1996 ; Poczai et al., 2014 ; Browning and Bailey-Serres, 2015 ).…”

Section: Assembly Of Heterogeneous Ribosomesmentioning

confidence: 99%

Systematic Review of Plant Ribosome Heterogeneity and Specialization

et al. 2020

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Plants dedicate a high amount of energy and resources to the production of ribosomes. Historically, these multi-protein ribosome complexes have been considered static protein synthesis machines that are not subject to extensive regulation but only read mRNA and produce polypeptides accordingly. New and increasing evidence across various model organisms demonstrated the heterogeneous nature of ribosomes. This heterogeneity can constitute specialized ribosomes that regulate mRNA translation and control protein synthesis. A prominent example of ribosome heterogeneity is seen in the model plant, Arabidopsis thaliana , which, due to genome duplications, has multiple paralogs of each ribosomal protein (RP) gene. We support the notion of plant evolution directing high RP paralog divergence toward functional heterogeneity, underpinned in part by a vast resource of ribosome mutants that suggest specialization extends beyond the pleiotropic effects of single structural RPs or RP paralogs. Thus, Arabidopsis is a highly suitable model to study this phenomenon. Arabidopsis enables reverse genetics approaches that could provide evidence of ribosome specialization. In this review, we critically assess evidence of plant ribosome specialization and highlight steps along ribosome biogenesis in which heterogeneity may arise, filling the knowledge gaps in plant science by providing advanced insights from the human or yeast fields. We propose a data analysis pipeline that infers the heterogeneity of ribosome complexes and deviations from canonical structural compositions linked to stress events. This analysis pipeline can be extrapolated and enhanced by combination with other high-throughput methodologies, such as proteomics. Technologies, such as kinetic mass spectrometry and ribosome profiling, will be necessary to resolve the temporal and spatial aspects of translational regulation while the functional features of ribosomal subpopulations will become clear with the combination of reverse genetics and systems biology approaches.

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Histone methyltransferases regulating rRNA gene dose and dosage control in Arabidopsis

et al. 2012

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Eukaryotes have hundreds of nearly identical 45S ribosomal RNA (rRNA) genes, each encoding the 18S, 5.8S, and 25S catalytic rRNAs. Because cellular demands for ribosomes and protein synthesis vary during development, the number of active rRNA genes is subject to dosage control. In genetic hybrids, one manifestation of dosage control is nucleolar dominance, an epigenetic phenomenon in which the rRNA genes of one progenitor are repressed. For instance, in Arabidopsis suecica, the allotetraploid hybrid of Arabidopsis thaliana and Arabidopsis arenosa, the A. thaliana-derived rRNA genes are selectively silenced. An analogous phenomenon occurs in nonhybrid A. thaliana, in which specific classes of rRNA gene variants are inactivated. An RNA-mediated knockdown screen identified SUVR4 {SUPPRESSOR OF VARIEGATION 3-9 [SU(VAR)3-9]-RELATED 4} as a histone H3 Lys 9 (H3K9) methyltransferase required for nucleolar dominance in A. suecica. H3K9 methyltransferases are also required for variant-specific silencing in A. thaliana, but SUVH5 [SU(VAR)3-9 HOMOLOG 5] and SUVH6, rather than SUVR4, are the key activities in this genomic context. Mutations disrupting the H3K27 methyltransferases ATXR5 or ATXR6 affect which rRNA gene variants are expressed or silenced, and in atxr5 atxr6 double mutants, dominance relationships among variants are reversed relative to wild type. Interestingly, these changes in gene expression are accompanied by changes in the relative abundance of the rRNA gene variants at the DNA level, including overreplication of the normally silenced class and decreased abundance of the normally dominant class. Collectively, our results indicate that histone methylation can affect both the doses of different variants and their differential silencing through the choice mechanisms that achieve dosage control.

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Polymerase I Transcription

Cited by 4 publications

References 142 publications

Ribosome Biogenesis in Plants: From Functional 45S Ribosomal DNA Organization to Ribosome Assembly Factors

Ribosome Biogenesis in Plants: From Functional 45S Ribosomal DNA Organization to Ribosome Assembly Factors

Systematic Review of Plant Ribosome Heterogeneity and Specialization

Histone methyltransferases regulating rRNA gene dose and dosage control in Arabidopsis

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