scholarly journals Base pairing interactions between substrate RNA and H/ACA guide RNA modulate the kinetics of pseudouridylation, but not the affinity of substrate binding by H/ACA small nucleolar Ribonucleoproteins

2019 ◽  
Author(s):  
Erin Katelyn Kelly ◽  
Dominic Philip Czekay ◽  
Ute Kothe
Keyword(s):  
Messenger Rna ◽  
Ribosome Biogenesis ◽  
Small Nuclear Rna ◽  
Base Pairing ◽  
Base Pairs ◽  
Guide Rna ◽  
Guide Rnas ◽  
Pairing Strength ◽  
Pairing Interactions ◽  
Time Courses

AbstractH/ACA small nucleolar ribonucleoproteins (snoRNPs) pseudouridylate RNA in eukaryotes and archaea. They target many RNAs site-specifically through base-pairing interactions between H/ACA guide and substrate RNA. Besides ribosomal RNA (rRNA) and small nuclear RNA (snRNA), H/ACA snoRNPs are thought to also modify messenger RNA (mRNA) with potential impacts on gene expression. However, the base-pairing between known target RNAs and H/ACA guide RNAs varies widely in nature, and therefore the rules governing substrate RNA selection are still not fully understood. To provide quantitative insight into substrate RNA recognition, we systematically altered the sequence of a substrate RNA target by the Saccharomyces cerevisiae H/ACA guide RNA snR34. Time courses measuring pseudouridine formation revealed a gradual decrease in the initial velocity of pseudouridylation upon reducing the number of base pairs between substrate and guide RNA. Changing or inserting nucleotides close to the target uridine severely impairs pseudouridine formation. Interestingly, filter binding experiments show that all substrate RNA variants bind to H/ACA snoRNPs with nanomolar affinity. Next, we showed that binding of inactive, near-cognate RNAs to H/ACA snoRNPs does not inhibit their activity for cognate RNAs, presumably because near-cognate RNAs dissociate rapidly. We discuss that the modulation of initial velocities by the base pairing strength might affect the order and efficiency of pseudouridylation in rRNA during ribosome biogenesis. Moreover, the binding of H/ACA snoRNPs to near-cognate RNAs may be a mechanism to search for cognate target sites. Together, our data provide critical information to aid in the prediction of productive H/ACA guide – substrate RNA pairs.

scholarly journals RNA base pairing complexity in living cells visualized by correlated chemical probing

2019 ◽  
Author(s):  
Anthony M. Mustoe ◽  
Nicole Lama ◽  
Patrick S. Irving ◽  
Samuel W. Olson ◽  
Kevin M. Weeks
Keyword(s):  
Single Molecule ◽  
Rna Structure ◽  
Dimethyl Sulfate ◽  
Detection Methods ◽  
Base Pairing ◽  
Base Pairs ◽  
Chemical Probing ◽  
Pairing Interactions ◽  
In Cells

ABSTRACTRNA structure and dynamics are critical to biological function. However, strategies for determining RNA structure in vivo are limited, with established chemical probing and newer duplex detection methods each having notable deficiencies. Here we convert the common reagent dimethyl sulfate (DMS) into a useful probe of all four RNA nucleotides. Building on this advance, we introduce PAIR-MaP, which uses single-molecule correlated chemical probing to directly detect base pairing interactions in cells. PAIR-MaP has superior resolution and accuracy compared to alternative experiments, can resolve alternative pairing interactions of structurally dynamic RNAs, and enables highly accurate structure modeling, including of RNAs containing multiple pseudoknots and extensively bound by proteins. Application of PAIR-MaP to human RNase MRP and two bacterial mRNA 5'-UTRs reveals new functionally important and complex structures undetectable by conventional analyses. PAIR-MaP is a powerful, experimentally concise, and broadly applicable strategy for directly visualizing RNA base pairs and dynamics in cells.

scholarly journals snR30/U17 Small Nucleolar Ribonucleoprotein: A Critical Player during Ribosome Biogenesis

Cells ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 2195
Author(s):  
Timothy John Vos ◽  
Ute Kothe
Keyword(s):  
Ribosome Biogenesis ◽  
Current Knowledge ◽  
Small Subunit ◽  
Future Research ◽  
Unique Role ◽  
Ribosome Synthesis ◽  
Guide Rna ◽  
Guide Rnas ◽  
Ssu Processome ◽  
Nucleolar Rna

The small nucleolar RNA snR30 (U17 in humans) plays a unique role during ribosome synthesis. Unlike most members of the H/ACA class of guide RNAs, the small nucleolar ribonucleoprotein (snoRNP) complex assembled on snR30 does not direct pseudouridylation of ribosomal RNA (rRNA), but instead snR30 is critical for 18S rRNA processing during formation of the small subunit (SSU) of the ribosome. Specifically, snR30 is essential for three pre-rRNA cleavages at the A0/01, A1/1, and A2/2a sites in yeast and humans, respectively. Accordingly, snR30 is the only essential H/ACA guide RNA in yeast. Here, we summarize our current knowledge about the interactions and functions of snR30, discuss what remains to be elucidated, and present two non-exclusive hypotheses on the possible molecular function of snR30 during ribosome biogenesis. First, snR30 might be responsible for recruiting other proteins including endonucleases to the SSU processome. Second, snR30 may contribute to the refolding of pre-rRNA into a required conformation that serves as a checkpoint during ribosome biogenesis facilitating pre-rRNA cleavage. In both scenarios, the snR30 snoRNP may have scaffolding and RNA chaperoning activity. In conclusion, the snR30 snoRNP is a crucial player with an unknown molecular mechanism during ribosome synthesis, posing many interesting future research questions.

scholarly journals RNA base-pairing complexity in living cells visualized by correlated chemical probing

2019 ◽  
Vol 116 (49) ◽  
pp. 24574-24582 ◽  
Author(s):  
Anthony M. Mustoe ◽  
Nicole N. Lama ◽  
Patrick S. Irving ◽  
Samuel W. Olson ◽  
Kevin M. Weeks
Keyword(s):  
Single Molecule ◽  
Rna Structure ◽  
Messenger Rna ◽  
Dimethyl Sulfate ◽  
Detection Methods ◽  
Base Pairing ◽  
Chemical Probing ◽  
Pairing Interactions ◽  
In Cells

RNA structure and dynamics are critical to biological function. However, strategies for determining RNA structure in vivo are limited, with established chemical probing and newer duplex detection methods each having deficiencies. Here we convert the common reagent dimethyl sulfate into a useful probe of all 4 RNA nucleotides. Building on this advance, we introduce PAIR-MaP, which uses single-molecule correlated chemical probing to directly detect base-pairing interactions in cells. PAIR-MaP has superior resolution compared to alternative experiments, can resolve multiple sets of pairing interactions for structurally dynamic RNAs, and enables highly accurate structure modeling, including of RNAs containing multiple pseudoknots and extensively bound by proteins. Application of PAIR-MaP to human RNase MRP and 2 bacterial messenger RNA 5′ untranslated regions reveals functionally important and complex structures undetected by prior analyses. PAIR-MaP is a powerful, experimentally concise, and broadly applicable strategy for directly visualizing RNA base pairs and dynamics in cells.

scholarly journals Localization and structure of endonuclease cleavage sites involved in the processing of the rat 32S precursor to ribosomal RNA

1984 ◽  
Vol 220 (1) ◽  
pp. 105-116 ◽  
Author(s):  
K V Hadjiolova ◽  
O I Georgiev ◽  
V V Nosikov ◽  
A A Hadjiolov
Keyword(s):  
Secondary Structure ◽  
Ribosome Biogenesis ◽  
Rrna Gene ◽  
Computer Search ◽  
Cleavage Sites ◽  
Base Pairing ◽  
Base Pairs ◽  
S1 Nuclease ◽  
Evolutionarily Conserved ◽  
Domain I

The initial endonuclease cleavage site in 32 S pre-rRNA (precursor to rRNA) is located within the rate rDNA sequence by S1-nuclease protection mapping of purified nucleolar 28 S rRNA and 12 S pre-rRNA. The heterogeneous 5′- and 3′-termini of these rRNA abut and map within two CTC motifs in tSi2 (internal transcribed spacer 2) located at 50-65 and 4-20 base-pairs upstream from the homogeneous 5′-end of the 28 S rRNA gene. These results show that multiple endonuclease cleavages occur at CUC sites in tSi2 to generate 28 S rRNA and 12 S pre-rRNA with heterogeneous 5′- and 3′-termini, respectively. These molecules have to be processed further to yield mature 28 S and 5.8 S rRNA. Thermal-denaturation studies revealed that the base-pairing association in the 12 S pre-rRNA:28 S rRNA complex is markedly stronger than that in the 5.8 S:28 S rRNA complex. The sequence of about one-quarter (1322 base-pairs) of the 5′-part of the rat 28 S rDNA was determined. A computer search reveals the possibility that the cleavage sites in the CUC motifs are single-stranded, flanked by strongly base-paired GC tracts, involving tSi2 and 28 S rRNA sequences. The subsequent nuclease cleavages, generating the termini of mature rRNA, seem to be directed by secondary-structure interactions between 5.8 S and 28 S rRNA segments in pre-rRNA. An analysis for base-pairing among evolutionarily conserved sequences in 32 S pre-rRNA suggests that the cleavages yielding mature 5.8 S and 28 S rRNA are directed by base-pairing between (i) the 3′-terminus of 5.8 S rRNA and the 5′-terminus of 28 S rRNA and (ii) the 5′-terminus of 5.8 S rRNA and internal sequences in domain I of 28 S rRNA. A general model for primary- and secondary-structure interactions in pre-rRNA processing is proposed, and its implications for ribosome biogenesis in eukaryotes are briefly discussed.

Compensatory mutations suggest that base-pairing with a small nuclear RNA is required to form the 3′ end of H3 messenger RNA

Nature ◽  
1986 ◽  
Vol 323 (6091) ◽  
pp. 777-781 ◽  
Author(s):  
Fred Schaufele ◽  
Gregory M. Gilmartin ◽  
Willi Bannwarth ◽  
Max L. Birnstiel
Keyword(s):  
Messenger Rna ◽  
Small Nuclear Rna ◽  
Base Pairing ◽  
Nuclear Rna ◽  
Compensatory Mutations

scholarly journals SnoRNA guide activities–real and ambiguous

2021 ◽  
Author(s):  
Svetlana Deryusheva ◽  
Gaelle JS Talross ◽  
Joseph G. Gall
Keyword(s):  
Cajal Body ◽  
Yeast Cells ◽  
Target Sequence ◽  
Specific Substrate ◽  
Rna Modifications ◽  
Base Pairing ◽  
Strong Base ◽  
U2 Snrna ◽  
Guide Rna ◽  
Guide Rnas

In eukaryotes, rRNAs and spliceosomal snRNAs are heavily modified posttranscriptionally. Pseudouridylation and 2′-O-methylation are the most abundant types of RNA modifications. They are mediated by modification guide RNAs, also known as small nucleolar (sno)RNAs and small Cajal body-specific (sca)RNAs. We used yeast and vertebrate cells to test guide activities predicted for a number of snoRNAs, based on their regions of complementarity with rRNAs. We showed that human SNORA24 is a genuine guide RNA for 18S-ψ609, despite some non-canonical base-pairing with its target. At the same time, we found quite a few snoRNAs that have the ability to base-pair with rRNAs and can induce predicted modifications in artificial substrate RNAs, but do not modify the same target sequence within endogenous rRNA molecules. Furthermore, certain fragments of rRNAs can be modified by the endogenous yeast modification machinery when inserted into an artificial backbone RNA, even though the same sequences are not modified in endogenous yeast rRNAs. In Xenopus cells a guide RNA generated from scaRNA, but not from snoRNA, could induce an additional pseudouridylation of U2 snRNA at position 60; both guide RNAs were equally active on a U2 snRNA-specific substrate in yeast cells. Thus, posttranscriptional modification of functionally important RNAs, such as rRNAs and snRNAs, is highly regulated and more complex than simply strong base-pairing between a guide RNA and substrate RNA. We discuss possible regulatory roles for these unexpected modifications.

scholarly journals Trypanosome RNA Editing: Simple Guide RNA Features Enhance U Deletion 100-Fold

2001 ◽  
Vol 21 (3) ◽  
pp. 884-892 ◽  
Author(s):  
Jorge Cruz-Reyes ◽  
Alevtina Zhelonkina ◽  
Laura Rusche ◽  
Barbara Sollner-Webb
Keyword(s):  
Rna Editing ◽  
Central Region ◽  
Marked Improvement ◽  
Base Pairing ◽  
Guide Rna ◽  
Guide Rnas ◽  
Evolutionary Forces

ABSTRACT Trypanosome RNA editing is a massive processing of mRNA by U deletion and U insertion, directed by trans-acting guide RNAs (gRNAs). A U deletion cycle and a U insertion cycle have been reproduced in vitro using synthetic ATPase (A6) pre-mRNA and gRNA. Here we examine which gRNA features are important for this U deletion. We find that, foremost, this editing depends critically on the single-stranded character of a few gRNA and a few mRNA residues abutting the anchor duplex, a feature not previously appreciated. That plus any base-pairing sequence to tether the upstream mRNA are all the gRNA needs to direct unexpectedly efficient in vitro U deletion, using either the purified editing complex or whole extract. In fact, our optimized gRNA constructs support faithful U deletion up to 100 times more efficiently than the natural gRNA, and they can edit the majority of mRNA molecules. This is a marked improvement of in vitro U deletion, in which previous artificial gRNAs were no more active than natural gRNA and the editing efficiencies were at most a few percent. Furthermore, this editing is not stimulated by most other previously noted gRNA features, including its potential ligation bridge, 3′ OH moiety, any U residues in the tether, the conserved structure of the central region, or proteins that normally bind these regions. Our data also have implications about evolutionary forces active in RNA editing.

scholarly journals Nucleolar Factors Direct the 2′-O-Ribose Methylation and Pseudouridylation of U6 Spliceosomal RNA

1999 ◽  
Vol 19 (10) ◽  
pp. 6906-6917 ◽  
Author(s):  
Philippe Ganot ◽  
Beáta E. Jády ◽  
Marie-Line Bortolin ◽  
Xavier Darzacq ◽  
Tamás Kiss
Keyword(s):  
Small Nuclear Rna ◽  
Guide Rna ◽  
Guide Rnas ◽  
Trafficking Pathway ◽  
5.8S Rrna ◽  
Nuclear Rna ◽  
Nucleolar Rna ◽  
Correct Target ◽  
Selection Of ◽  
U6 Rna

ABSTRACT The nucleolus has long been known as a functionally highly specialized subnuclear compartment where synthesis, posttranscriptional modification, and processing of cytoplasmic rRNAs take place. In this study, we demonstrate that the nucleolus contains all thetrans-acting factors that are responsible for the accurate and efficient synthesis of the eight 2′-O-methylated nucleotides and three pseudouridine residues carried by the mammalian U6 spliceosomal small nuclear RNA. Factors mediating the formation of pseudouridine residues in the U3 small nucleolar RNA are also present and functionally active in the nucleolus. For selection of the correct target nucleotides in the U6 and U3 RNAs, the nucleolar 2′-O-methylation and pseudouridylation factors rely on short sequences located around the target nucleotide to be modified. This observation further underscores a recently proposed role for small nucleolar guide RNAs in the 2′-O-methylation of the U6 spliceosomal RNA (K. T. Tycowski, Z.-H. You, P. J. Graham, and J. A. Steitz, Mol. Cell 2:629–638, 1998). We demonstrate that a novel 2′-O-methylated nucleotide can be generated in the yeast U6 RNA by use of an artificial 2′-O-methylation small nucleolar guide RNA. We also show that a short fragment of the 5.8S rRNA, when expressed as part of the human U6 RNA, is faithfully 2′-O-methylated and pseudouridylated. These results are most consistent with a trafficking pathway in which the U6 spliceosomal RNA cycles through the nucleolus to undergo nucleolar RNA-directed modifications.

scholarly journals SnoRNA guide activities – real and ambiguous

RNA ◽  
2021 ◽  
pp. rna.078916.121
Author(s):  
Svetlana Deryusheva ◽  
Gaelle JS Talross ◽  
Joseph G. Gall
Keyword(s):  
Cajal Body ◽  
Yeast Cells ◽  
Target Sequence ◽  
Specific Substrate ◽  
Rna Modifications ◽  
Base Pairing ◽  
Strong Base ◽  
U2 Snrna ◽  
Guide Rna ◽  
Guide Rnas

In eukaryotes, rRNAs and spliceosomal snRNAs are heavily modified posttranscriptionally. Pseudouridylation and 2’-O-methylation are the most abundant types of RNA modifications. They are mediated by modification guide RNAs, also known as small nucleolar (sno)RNAs and small Cajal body-specific (sca)RNAs. We used yeast and vertebrate cells to test guide activities predicted for a number of snoRNAs, based on their regions of complementarity with rRNAs. We showed that human SNORA24 is a genuine guide RNA for 18S-ψ609, despite some non-canonical base-pairing with its target. At the same time, we found quite a few snoRNAs that have the ability to base-pair with rRNAs and can induce predicted modifications in artificial substrate RNAs, but do not modify the same target sequence within endogenous rRNA molecules. Furthermore, certain fragments of rRNAs can be modified by the endogenous yeast modification machinery when inserted into an artificial backbone RNA, even though the same sequences are not modified in endogenous yeast rRNAs. In Xenopus cells a guide RNA generated from scaRNA, but not from snoRNA, could induce an additional pseudouridylation of U2 snRNA at position 60; both guide RNAs were equally active on a U2 snRNA-specific substrate in yeast cells. Thus, posttranscriptional modification of functionally important RNAs, such as rRNAs and snRNAs, is highly regulated and more complex than simply strong base-pairing between a guide RNA and substrate RNA. We discuss possible regulatory roles for these unexpected modifications.

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