Polymerase I Transcription

Sáez‐Vasquez, Julio; Echeverrı́a, Manuel

doi:10.1002/9780470988886.ch7

Cited by 2 publications

(4 citation statements)

References 133 publications

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“…Here we examine accumulation of 45S pre-rRNA and processing in the 3′ETS region in Atnuc-L1-1 plants because 3′ETS cleavage is a co-transcriptional event that releases 45S pre-rRNA precursor [6]. To verify accumulation of these precursors in Atnuc-L1-1 plants we performed northern blot analysis using oligonucleotide probes p34 and p35 that specifically match 5′ETS sequences located either upstream and downstream from the P cleavage site, respectively, and oligonucleotide p41 to detects 3′ETS region (position shown in Figure 1 and Figure S4).…”

Section: Resultsmentioning

confidence: 99%

“…Bar = 10 µm. In Panel pre-rRNA, the accumulated small punctuate loci dispersed throughout the nucleolus of Atnuc-L1 plants can be compared with the multiple transcriptional initiation sites detected by BrU incorporation in pea and other species [6]. In Panel α-24.3, we observed a localization of the 24.3 kDa subunit in “focus” both in the nucleolus of WT and AtnucL1 plant mutants (Panel α-PolI).…”

Section: Supporting Informationmentioning

confidence: 87%

“…Analysis of complete IGS sequences reveals considerable length and sequence heterogeneity in different plant species, including radish, wheat, A. thaliana , Brassica , Nicotiana and Solanum species [6]. However, all ribosomal IGS contain repeated sequences.…”

Section: Introductionmentioning

confidence: 99%

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Nucleolin Is Required for DNA Methylation State and the Expression of rRNA Gene Variants in Arabidopsis thaliana

et al. 2010

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In eukaryotes, 45S rRNA genes are arranged in tandem arrays in copy numbers ranging from several hundred to several thousand in plants. Although it is clear that not all copies are transcribed under normal growth conditions, the molecular basis controlling the expression of specific sets of rRNA genes remains unclear. Here, we report four major rRNA gene variants in Arabidopsis thaliana. Interestingly, while transcription of one of these rRNA variants is induced, the others are either repressed or remain unaltered in A. thaliana plants with a disrupted nucleolin-like protein gene (Atnuc-L1). Remarkably, the most highly represented rRNA gene variant, which is inactive in WT plants, is reactivated in Atnuc-L1 mutants. We show that accumulated pre–rRNAs originate from RNA Pol I transcription and are processed accurately. Moreover, we show that disruption of the AtNUC-L1 gene induces loss of symmetrical DNA methylation without affecting histone epigenetic marks at rRNA genes. Collectively, these data reveal a novel mechanism for rRNA gene transcriptional regulation in which the nucleolin protein plays a major role in controlling active and repressed rRNA gene variants in Arabidopsis.

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Section: Resultsmentioning

confidence: 99%

Section: Supporting Informationmentioning

confidence: 87%

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Nucleolin Is Required for DNA Methylation State and the Expression of rRNA Gene Variants in Arabidopsis thaliana

et al. 2010

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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 (Saéz-Vaśquez and Echeverrıá, 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: Variation Of Ribosomal Rnamentioning

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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Polymerase I Transcription

Cited by 2 publications

References 133 publications

Nucleolin Is Required for DNA Methylation State and the Expression of rRNA Gene Variants in Arabidopsis thaliana

Nucleolin Is Required for DNA Methylation State and the Expression of rRNA Gene Variants in Arabidopsis thaliana

Systematic Review of Plant Ribosome Heterogeneity and Specialization

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