scholarly journals ADAR2-mediated editing of RNA substrates in the nucleolus is inhibited by C/D small nucleolar RNAs

2005 ◽  
Vol 169 (5) ◽  
pp. 745-753 ◽  
Author(s):  
Patrice Vitali ◽  
Eugenia Basyuk ◽  
Elodie Le Meur ◽  
Edouard Bertrand ◽  
Françoise Muscatelli ◽  
...  
Keyword(s):  
Rna Editing ◽  
Serotonin Receptor ◽  
Small Nucleolar Rnas ◽  
Ribonucleoprotein Particle ◽  
Subcellular Targeting ◽  
Adenosine Deaminases ◽  
Bona Fide ◽  
Cellular Compartments ◽  
Nucleolar Rna ◽  
Nucleolar Rnas

Posttranscriptional, site-specific adenosine to inosine (A-to-I) base conversions, designated as RNA editing, play significant roles in generating diversity of gene expression. However, little is known about how and in which cellular compartments RNA editing is controlled. Interestingly, the two enzymes that catalyze RNA editing, adenosine deaminases that act on RNA (ADAR) 1 and 2, have recently been demonstrated to dynamically associate with the nucleolus. Moreover, we have identified a brain-specific small RNA, termed MBII-52, which was predicted to function as a nucleolar C/D RNA, thereby targeting an A-to-I editing site (C-site) within the 5-HT2C serotonin receptor pre-mRNA for 2′-O-methylation. Through the subcellular targeting of minigenes that contain natural editing sites, we show that ADAR2- but not ADAR1-mediated RNA editing occurs in the nucleolus. We also demonstrate that MBII-52 forms a bona fide small nucleolar ribonucleoprotein particle that specifically decreases the efficiency of RNA editing by ADAR2 at the targeted C-site. Our data are consistent with a model in which C/D small nucleolar RNA might play a role in the regulation of RNA editing.

scholarly journals Are Small Nucleolar RNAs “CRISPRable”? A Report on Box C/D Small Nucleolar RNA Editing in Human Cells

2019 ◽  
Vol 10 ◽  
Author(s):  
Julia A. Filippova ◽  
Anastasiya M. Matveeva ◽  
Evgenii S. Zhuravlev ◽  
Evgenia A. Balakhonova ◽  
Daria V. Prokhorova ◽  
...  
Keyword(s):  
Rna Editing ◽  
Human Cells ◽  
Small Nucleolar Rnas ◽  
Small Nucleolar Rna ◽  
Nucleolar Rna ◽  
Nucleolar Rnas

Three new small nucleolar RNAs that are psoralen cross-linked in vivo to unique regions of pre-rRNA

1993 ◽  
Vol 13 (7) ◽  
pp. 4382-4390
Author(s):  
O J Rimoldi ◽  
B Raghu ◽  
M K Nag ◽  
G L Eliceiri
Keyword(s):  
Small Rnas ◽  
18S Rrna ◽  
Rnase H ◽  
Antisense Oligodeoxynucleotide ◽  
28S Rrna ◽  
Small Nucleolar Rnas ◽  
Rrna Sequence ◽  
Nucleolar Rna ◽  
Nucleolar Rnas

We have recently described three novel human small nucleolar RNA species with unique nucleotide sequences, which were named E1, E2, and E3. The present article describes specific psoralen photocross-linking in whole HeLa cells of E1, E2, and E3 RNAs to nucleolar pre-rRNA. These small RNAs were cross-linked to different sections of pre-rRNA. E1 RNA was cross-linked to two segments of nucleolar pre-rRNA; one was within residues 697 to 1163 of the 5' external transcribed spacer, and the other one was between nucleotides 664 and 1021 of the 18S rRNA sequence. E2 RNA was cross-linked to a region within residues 3282 to 3667 of the 28S rRNA sequence. E3 RNA was cross-linked to a sequence between positions 1021 and 1639 of the 18S rRNA sequence. Primer extension analysis located psoralen adducts in E1, E2, and E3 RNAs that were enriched in high-molecular-weight fractions of nucleolar RNA. Some of these psoralen adducts might be cross-links of E1, E2, and E3 RNAs to large nucleolar RNA. Antisense oligodeoxynucleotide-targeted RNase H digestion of nucleolar extracts revealed accessible segments in these three small RNAs. The accessible regions were within nucleotide positions 106 to 130 of E1 RNA, positions 24 to 48 and 42 to 66 of E2 RNA, and positions 7 to 16 and about 116 to 122 of E3 RNA. Some of the molecules of these small nucleolar RNAs sedimented as if associated with larger structures when both nondenatured RNA and a nucleolar extract were analyzed.

scholarly journals Processing of the Precursors to Small Nucleolar RNAs and rRNAs Requires Common Components

1998 ◽  
Vol 18 (3) ◽  
pp. 1181-1189 ◽  
Author(s):  
Elisabeth Petfalski ◽  
Thomas Dandekar ◽  
Yves Henry ◽  
David Tollervey
Keyword(s):  
Small Nucleolar Rnas ◽  
Rrna Processing ◽  
5.8S Rrna ◽  
Genes Encoding ◽  
Sequences Analysis ◽  
Upstream Processing ◽  
Exonuclease Digestion ◽  
Nucleolar Rna ◽  
Nucleolar Rnas ◽  
Common Components

ABSTRACT The genes encoding the small nucleolar RNA (snoRNA) species snR190 and U14 are located close together in the genome of Saccharomyces cerevisiae. Here we report that these two snoRNAs are synthesized by processing of a larger common transcript. In strains mutant for two 5′→3′ exonucleases, Xrn1p and Rat1p, families of 5′-extended forms of snR190 and U14 accumulate; these have 5′ extensions of up to 42 and 55 nucleotides, respectively. We conclude that the 5′ ends of both snR190 and U14 are generated by exonuclease digestion from upstream processing sites. In contrast to snR190 and U14, the snoRNAs U18 and U24 are excised from the introns of pre-mRNAs which encode proteins in their exonic sequences. Analysis of RNA extracted from a dbr1-Δ strain, which lacks intron lariat-debranching activity, shows that U24 can be synthesized only from the debranched lariat. In contrast, a substantial level of U18 can be synthesized in the absence of debranching activity. The 5′ ends of these snoRNAs are also generated by Xrn1p and Rat1p. The same exonucleases are responsible for the degradation of several excised fragments of the pre-rRNA spacer regions, in addition to generating the 5′ end of the 5.8S rRNA. Processing of the pre-rRNA and both intronic and polycistronic snoRNAs therefore involves common components.

Small nucleolar RNA

1995 ◽  
Vol 73 (11-12) ◽  
pp. 845-858 ◽  
Author(s):  
Susan A. Gerbi
Keyword(s):  
Rna Polymerase Ii ◽  
Binding Sites ◽  
Ribosome Biogenesis ◽  
Internal Transcribed Spacers ◽  
28S Rrna ◽  
Small Nucleolar Rnas ◽  
Rrna Processing ◽  
Conserved Sequence ◽  
Nucleolar Rna ◽  
Nucleolar Rnas

A growing list of small nucleolar RNAs (snoRNAs) has been characterized in eukaryotes. They are transcribed by RNA polymerase II or III; some snoRNAs are encoded in the introns of other genes. The nonintronic polymerase II transcribed snoRNAs receive a trimethylguanosine cap, probably in the nucleus, and move to the nucleolus. snoRNAs are complexed with proteins, sometimes including fibrillarin. Localization and maintenance in the nucleolus of some snoRNAs requires the presence of initial precursor rRNA (pre-rRNA). Many snoRNAs have conserved sequence boxes C and D and a 3′ terminal stem; the roles of these features are discussed. Functional assays done for a few snoRNAs indicate their roles in rRNA processing for cleavage of the external and internal transcribed spacers (ETS and ITS). U3 is the most abundant snoRNA and is needed for cleavage of ETS1 and ITS1; experimental results on U3 binding sites in pre-rRNA are reviewed. 18S rRNA production also needs U14, U22, and snR30 snoRNAs, whereas U8 snoRNA is needed for 5.8S and 28S rRNA production. Other snoRNAs that are complementary to 18S or 28S rRNA might act as chaperones to mediate RNA folding. Whether snoRNAs join together in a large rRNA processing complex (the "processome") is not yet clear. It has been hypothesized that such complexes could anchor the ends of loops in pre-rRNA containing 18S or 28S rRNA, thereby replacing base-paired stems found in pre-rRNA of prokaryotes.Key words: RNA processing, small nucleolar RNAs, nucleolus, ribosome biogenesis, rRNA processing complex.

scholarly journals Synthesis and Assembly of the Box C+D Small Nucleolar RNPs

2000 ◽  
Vol 20 (8) ◽  
pp. 2650-2659 ◽  
Author(s):  
Denis L. J. Lafontaine ◽  
David Tollervey
Keyword(s):  
18S Rrna ◽  
Protein A ◽  
Small Nucleolar Rnas ◽  
Rrna Processing ◽  
Bona Fide ◽  
Polycistronic Transcripts ◽  
Nucleolar Rnas

ABSTRACT Two core small nucleolar RNP (snoRNP) proteins, Nop1p (fibrillarin in vertebrates) and Nop58p (also known as Nop5p) have previously been reported to be specifically associated with the box C+D class of small nucleolar RNAs (snoRNAs). Here we report that Nop56p, a protein related in sequence to Nop58p, is a bona fide box C+D snoRNP component; all tested box C+D snoRNAs were coprecipitated with protein A-tagged Nop56p. Analysis of in vivo snoRNP assembly indicated that Nop56p was stably associated with the snoRNAs only in the presence of Nop1p. In contrast, Nop58p and Nop1p associate independently with the snoRNAs. Genetic depletion of Nop56p resulted in inhibition of early pre-rRNA processing events at sites A0, A1, and A2 and mild depletion of 18S rRNA. However, Nop56p depletion did not lead to codepletion of the box C+D snoRNAs. This is in contrast to Nop58p, which was required for the accumulation of all tested box C+D snoRNAs. Unexpectedly, we found that Nop1p was specifically required for the synthesis and accumulation of box C+D snoRNAs processed from pre-mRNA introns and polycistronic transcripts.

scholarly journals Immunopurified Small Nucleolar Ribonucleoprotein Particles Pseudouridylate rRNA Independently of Their Association with Phosphorylated Nopp140

2002 ◽  
Vol 22 (24) ◽  
pp. 8457-8466 ◽  
Author(s):  
Chen Wang ◽  
Charles C. Query ◽  
U. Thomas Meier
Keyword(s):  
Cajal Body ◽  
Small Nucleolar Rnas ◽  
Ribonucleoprotein Particle ◽  
Vitro Assay ◽  
Body Protein ◽  
Core Proteins ◽  
Layer Chromatography ◽  
Nucleolar Rnas

ABSTRACT The isomerization of up to 100 uridines to pseudouridines (Ψs) in eukaryotic rRNA is guided by a similar number of box H/ACA small nucleolar RNAs (snoRNAs), each forming a unique small nucleolar ribonucleoprotein particle (snoRNP) with the same four core proteins, NAP57 (also known as dyskerin or Cbf5p), GAR1, NHP2, and NOP10. Additionally, the nucleolar and Cajal body protein Nopp140 (Srp40p) associates with the snoRNPs. To understand the role of these factors in pseudouridylation, we established an in vitro assay system. Short site-specifically 32P-labeled rRNA substrates were incubated with subcellular fractions, and the conversion of uridine to Ψ was monitored by thin-layer chromatography after digestion to single nucleotides. Immunopurified box H/ACA core particles were sufficient for the reaction. SnoRNPs associated quantitatively and reversibly with Nopp140. However, pseudouridylation activity was independent of Nopp140, consistent with a chaperoning role for this highly phosphorylated protein. Although up to 14 bp between the snoRNA and rRNA were required for the in vitro reaction, rRNA pseudouridylation and release occurred in the absence of ATP and magnesium. These data suggest that substrate release takes place without RNA helicase activity but may be aided by the snoRNP core proteins.

scholarly journals Mapping targets for small nucleolar RNAs in yeast

2018 ◽  
Vol 3 ◽  
pp. 120
Author(s):  
Tatiana Dudnakova ◽  
Hywel Dunn-Davies ◽  
Rosie Peters ◽  
David Tollervey
Keyword(s):  
Binding Sites ◽  
High Energy ◽  
Small Nucleolar Rnas ◽  
High Confidence ◽  
Regulatory Interactions ◽  
Uv Crosslinking ◽  
Rna Targets ◽  
Bona Fide ◽  
Target Binding ◽  
Nucleolar Rnas

Background: Recent analyses implicate changes in the expression of the box C/D class of small nucleolar RNAs (snoRNAs) in several human diseases. Methods: Here we report the identification of potential novel RNA targets for box C/D snoRNAs in budding yeast, using the approach of UV crosslinking and sequencing of hybrids (CLASH) with the snoRNP proteins Nop1, Nop56 and Nop58. We also developed a bioinformatics approach to filter snoRNA-target interactions for bona fide methylation guide interactions. Results: We recovered 241,420 hybrids, out of which 190,597 were classed as reproducible, high energy hybrids. As expected, the majority of snoRNA interactions were with the ribosomal RNAs (rRNAs). Following filtering, 117,047 reproducible hybrids included 51 of the 55 reported rRNA methylation sites. The majority of interactions at methylation sites were predicted to guide methylation. However, competing, potentially regulatory, binding was also identified. In marked contrast, following CLASH performed with the RNA helicase Mtr4 only 7% of snoRNA-rRNA interactions recovered were predicted to guide methylation. We propose that Mtr4 functions in dissociating inappropriate snoRNA-target interactions. Numerous snoRNA-snoRNA interactions were recovered, indicating potential cross regulation. The snoRNAs snR4 and snR45 were recently implicated in site-directed rRNA acetylation, and hybrids were identified adjacent to the acetylation sites. We also identified 1,368 reproducible snoRNA-mRNA interactions, representing 448 sites of interaction involving 39 snoRNAs and 382 mRNAs. Depletion of the snoRNAs U3, U14 or snR4 each altered the levels of numerous mRNAs. Targets identified by CLASH were over-represented among these species, but causality has yet to be established. Conclusions: Systematic mapping of snoRNA-target binding provides a catalogue of high-confidence binding sites and indicates numerous potential regulatory interactions.

scholarly journals In Vivo Identification of Nuclear Factors Interacting with the Conserved Elements of Box C/D Small Nucleolar RNAs

1998 ◽  
Vol 18 (2) ◽  
pp. 1023-1028 ◽  
Author(s):  
Elisa Caffarelli ◽  
Massimo Losito ◽  
Corinna Giorgi ◽  
Alessandro Fatica ◽  
Irene Bozzoni
Keyword(s):  
Rna Binding ◽  
Protein Gene ◽  
Molecular Size ◽  
Ribosomal Protein Gene ◽  
The Novel ◽  
Small Nucleolar Rnas ◽  
Nuclear Factors ◽  
Nucleolar Rna ◽  
Nucleolar Rnas

ABSTRACT The U16 small nucleolar RNA (snoRNA) is encoded by the third intron of the L1 (L4, according to the novel nomenclature) ribosomal protein gene of Xenopus laevis and originates from processing of the pre-mRNA in which it resides. The U16 snoRNA belongs to the box C/D snoRNA family, whose members are known to assemble in ribonucleoprotein particles (snoRNPs) containing the protein fibrillarin. We have utilized U16 snoRNA in order to characterize the factors that interact with the conserved elements common to the other members of the box C/D class. In this study, we have analyzed the in vivo assembly of U16 snoRNP particles in X. laevis oocytes and identified the proteins which interact with the RNA by label transfer after UV cross-linking. This analysis revealed two proteins, of 40- and 68-kDa apparent molecular size, which require intact boxes C and D together with the conserved 5′,3′-terminal stem for binding. Immunoprecipitation experiments showed that the p40 protein corresponds to fibrillarin, indicating that this protein is intimately associated with the RNA. We propose that fibrillarin and p68 represent the RNA-binding factors common to box C/D snoRNPs and that both proteins are essential for the assembly of snoRNP particles and the stabilization of the snoRNA.

scholarly journals Mapping targets for small nucleolar RNAs in yeast

2018 ◽  
Vol 3 ◽  
pp. 120 ◽  
Author(s):  
Tatiana Dudnakova ◽  
Hywel Dunn-Davies ◽  
Rosie Peters ◽  
David Tollervey
Keyword(s):  
Binding Sites ◽  
High Energy ◽  
Small Nucleolar Rnas ◽  
High Confidence ◽  
Regulatory Interactions ◽  
Uv Crosslinking ◽  
Rna Targets ◽  
Bona Fide ◽  
Target Binding ◽  
Nucleolar Rnas

Background: Recent analyses implicate changes in the expression of the box C/D class of small nucleolar RNAs (snoRNAs) in several human diseases. Methods: Here we report the identification of potential novel RNA targets for box C/D snoRNAs in budding yeast, using the approach of UV crosslinking and sequencing of hybrids (CLASH) with the snoRNP proteins Nop1, Nop56 and Nop58. We also developed a bioinformatics approach to filter snoRNA-target interactions for bona fide methylation guide interactions. Results: We recovered 241,420 hybrids, out of which 190,597 were classed as reproducible, high energy hybrids. As expected, the majority of snoRNA interactions were with the ribosomal RNAs (rRNAs). Following filtering, 117,047 reproducible hybrids included 51 of the 55 reported rRNA methylation sites. The majority of interactions at methylation sites were predicted to guide methylation. However, competing, potentially regulatory, binding was also identified. In marked contrast, following CLASH performed with the RNA helicase Mtr4 only 7% of snoRNA-rRNA interactions recovered were predicted to guide methylation. We propose that Mtr4 functions in dissociating inappropriate snoRNA-target interactions. Numerous snoRNA-snoRNA interactions were recovered, indicating potential cross regulation. The snoRNAs snR4 and snR45 were recently implicated in site-directed rRNA acetylation, and hybrids were identified adjacent to the acetylation sites. We also identified 1,368 reproducible snoRNA-mRNA interactions, representing 448 sites of interaction involving 39 snoRNAs and 382 mRNAs. Depletion of the snoRNAs U3, U14 or snR4 each altered the levels of numerous mRNAs. Targets identified by CLASH were over-represented among these species, but causality has yet to be established. Conclusions: Systematic mapping of snoRNA-target binding provides a catalogue of high-confidence binding sites and indicates numerous potential regulatory interactions.

scholarly journals Natural copy number differences of tandemly repeated small nucleolar RNAs in the Prader-Willi syndrome genomic region regulate individual behavioral responses in mammals

2018 ◽  
Author(s):  
Maryam Keshavarz ◽  
Rebecca Krebs-Wheaton ◽  
Peter Refki ◽  
Yoland Savriama ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Gaba Receptors ◽  
Copy Number ◽  
Serotonin Receptor ◽  
Target Genes ◽  
Phenotypic Variability ◽  
Inbred Mouse Strain ◽  
Prader Willi Syndrome ◽  
Small Nucleolar Rnas ◽  
Copy Numbers ◽  
Nucleolar Rnas

AbstractThe Prader-Willi Syndrome (PWS) gene region is an imprinted gene complex involved in behavioral, metabolic and osteogenic functions. We have analyzed here the variation of two families of regulatory small nucleolar RNAs (SNORD115 and SNORD116) that are coded within the PWS and are expressed from the paternal chromosome. They are organized in two tandemly repeated clusters which are naturally copy number variable between individuals. We find that the copy numbers at these loci correlate with repeatable individual test scores for anxiety that are considered to constitute a component of the “personality” of individuals. We show this for different populations and species of mice, cavies and for the anxiety component of personality tests in humans. This is also the case for an inbred mouse strain (C57Bl6) implying that copy number variation creates phenotypic variability even in an isogenic background. In transcriptome data from brain samples of this strain we find SNORD copy-number correlated regulation of target genes that are known to be involved in influencing behavior. SNORD115 has previously been suggested to regulate splicing of the serotonin receptor Htr2c and we confirm this in our data. For SNORD116 we provide evidence that it regulates the expression level of the chromatin regulator Ankrd11, which itself regulates GABA receptors, metabolic pathways, cell differentiation and osteogenesis. Intriguingly, we find that craniofacial shapes in mice correlate also with SNORD116 copy numbers. New copy number variants are generated at very high rates in mice, possibly at every generation, explaining why conventional genetic mapping could not detect this association. Our results suggest that the variable dosage of two regulatory RNAs are major determinants of individual behavioral differences and correlated traits in mammals.

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