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Project description:Post-transcriptional modifications of mRNA have emerged as novel regulators of gene expression. Pseudouridylation is the most abundant and widespread type of RNA modification in living organisms; however, the biological role of pseudouridine in mRNAs remains poorly understood. Here, we show that the pseudouridine synthase dyskerin associates with RNA polymerase II and is enriched at RNA polymerase II-transcribed genes genome-wide. As part of the H/ACA complex, dyskerin binds to thousands of mRNAs and is responsible for their pseudouridylation, an action that occurs in chromatin and does not appear to require a fully complementary guide RNA. In cells lacking dyskerin, pseudouridylation of mRNAs is reduced, while at the same time, de novo protein production is enhanced, indicating that pseudouridylation of mRNAs by dyskerin interferes with translation. Accordingly, pseudouridylation of an mRNA by dyskerin in vitro results in reduced translation of that mRNA. Moreover, in patients with dyskeratosis congenita caused by inherited mutations in the DKC1 gene, binding between mutated dyskerin and mRNAs is altered and pseudouridylation of mRNAs severely reduced. Our findings reveal a new critical function of the H/ACA complex in directing translation control with important implications for development and disease.
2023-06-26 | GSE211201 | GEO
Project description:Post-transcriptional modifications of mRNA have emerged as novel regulators of gene expression. Pseudouridylation is the most abundant and widespread type of RNA modification in living organisms; however, the biological role of pseudouridine in mRNAs remains poorly understood. Here, we show that the pseudouridine synthase dyskerin associates with RNA polymerase II and is enriched at RNA polymerase II-transcribed genes genome-wide. As part of the H/ACA complex, dyskerin binds to thousands of mRNAs and is responsible for their pseudouridylation, an action that occurs in chromatin and does not appear to require a fully complementary guide RNA. In cells lacking dyskerin, pseudouridylation of mRNAs is reduced, while at the same time, de novo protein production is enhanced, indicating that pseudouridylation of mRNAs by dyskerin interferes with translation. Accordingly, pseudouridylation of an mRNA by dyskerin in vitro results in reduced translation of that mRNA. Moreover, in patients with dyskeratosis congenita caused by inherited mutations in the DKC1 gene, binding between mutated dyskerin and mRNAs is altered and pseudouridylation of mRNAs severely reduced. Our findings reveal a new critical function of the H/ACA complex in directing translation control with important implications for development and disease.
2023-06-26 | GSE211199 | GEO
Project description:Post-transcriptional modifications of mRNA have emerged as novel regulators of gene expression. Pseudouridylation is the most abundant and widespread type of RNA modification in living organisms; however, the biological role of pseudouridine in mRNAs remains poorly understood. Here, we show that the pseudouridine synthase dyskerin associates with RNA polymerase II and is enriched at RNA polymerase II-transcribed genes genome-wide. As part of the H/ACA complex, dyskerin binds to thousands of mRNAs and is responsible for their pseudouridylation, an action that occurs in chromatin and does not appear to require a fully complementary guide RNA. In cells lacking dyskerin, pseudouridylation of mRNAs is reduced, while at the same time, de novo protein production is enhanced, indicating that pseudouridylation of mRNAs by dyskerin interferes with translation. Accordingly, pseudouridylation of an mRNA by dyskerin in vitro results in reduced translation of that mRNA. Moreover, in patients with dyskeratosis congenita caused by inherited mutations in the DKC1 gene, binding between mutated dyskerin and mRNAs is altered and pseudouridylation of mRNAs severely reduced. Our findings reveal a new critical function of the H/ACA complex in directing translation control with important implications for development and disease.
2023-06-26 | GSE211200 | GEO
Project description:Pseudouridine, the most abundant modified nucleoside in RNA, is synthesized by posttranscriptional isomerization of uridines. In eukaryotic RNAs, site-specific synthesis of pseudouridines is directed primarily by box H/ACA guide RNAs. In this study, we have identified 61 novel putative pseudouridylation guide RNAs by construction and characterization of a cDNA library of human box H/ACA RNAs. The majority of the new box H/ACA RNAs are predicted to direct pseudouridine synthesis in rRNAs and spliceosomal small nuclear RNAs. We can attribute RNA-directed modification to 79 of the 97 pseudouridylation sites present in the human 18S, 5.8S, and 28S rRNAs and to 11 of the 21 pseudouridines reported for the U1, U2, U4, U5, and U6 spliceosomal RNAs. We have also identified 12 novel box H/ACA RNAs which lack apparent target pseudouridines in rRNAs and small nuclear RNAs. These putative guide RNAs likely function in the pseudouridylation of some other types of cellular RNAs, suggesting that RNA-guided pseudouridylation is more general than assumed before. The genomic organization of the new box H/ACA RNA genes indicates that in human cells, all box H/ACA pseudouridylation guide RNAs are processed from introns of pre-mRNA transcripts which either encode a protein product or lack protein-coding capacity.
| S-EPMC480876 | biostudies-literature
Project description:Archaea and eukaryotes, in addition to protein-only enzymes, also possess ribonucleoproteins containing an H/ACA guide RNA plus four proteins that produce pseudouridine (Ψ). Although typical conditions for these RNA-guided reactions are known, certain variant conditions allow pseudouridylation. We used mutants of the two stem-loops of the Haloferax volcanii sR-h45 RNA that guides three pseudouridylations in 23S rRNA and their target RNAs to characterize modifications under various atypical conditions. The 5' stem-loop produces Ψ2605 and the 3' stem-loop produces Ψ1940 and Ψ1942. The latter two modifications require unpaired "UVUN" (V = A, C, or G) in the target and ACA box in the guide. Ψ1942 modification requires the presence of U1940 (or Ψ1940). Ψ1940 is not produced in the Ψ1942-containing substrate, suggesting a sequential modification of the two residues. The ACA box of a single stem-loop guide is not required when typically unpaired "UN" is up to 17 bases from its position in the guide, but is needed when the distance increases to 19 bases or the N is paired. However, ANA of the H box of the double stem-loop guide is needed even for the 5' typical pseudouridylation. The most 5' unpaired U in a string of U's is converted to Ψ, and in the absence of an unpaired U, a paired U can also be modified. Certain mutants of the Cbf5 protein affect pseudouridylation by the two stem-loops of sR-h45 differently. This study will help elucidate the conditions for production of nonconstitutive Ψ's, determine functions for orphan H/ACA RNAs and in target designing.
| S-EPMC7075261 | biostudies-literature
Project description:Site-specific pseudouridylation of human ribosomal and spliceosomal RNAs is directed by H/ACA guide RNAs composed of two hairpins carrying internal pseudouridylation guide loops. The distal "antisense" sequences of the pseudouridylation loop base-pair with the target RNA to position two unpaired target nucleotides 5'-UN-3', including the 5' substrate U, under the base of the distal stem topping the guide loop. Therefore, each pseudouridylation loop is expected to direct synthesis of a single pseudouridine (Ψ) in the target sequence. However, in this study, genetic depletion and restoration and RNA mutational analyses demonstrate that at least four human H/ACA RNAs (SNORA53, SNORA57, SCARNA8, and SCARNA1) carry pseudouridylation loops supporting efficient and specific synthesis of two consecutive pseudouridines (ΨΨ or ΨNΨ) in the 28S (Ψ3747/Ψ3749), 18S (Ψ1045/Ψ1046), and U2 (Ψ43/Ψ44 and Ψ89/Ψ91) RNAs, respectively. In order to position two substrate Us for pseudouridylation, the dual guide loops form alternative base-pairing interactions with their target RNAs. This remarkable structural flexibility of dual pseudouridylation loops provides an unexpected versatility for RNA-directed pseudouridylation without compromising its efficiency and accuracy. Besides supporting synthesis of at least 6% of human ribosomal and spliceosomal Ψs, evidence indicates that dual pseudouridylation loops also participate in pseudouridylation of yeast and archaeal rRNAs.
| S-EPMC8763049 | biostudies-literature
Project description:Pseudouridine (Psi) are frequently modified residues in RNA. In Eukarya, their formation is catalyzed by enzymes or by ribonucleoprotein complexes (RNPs) containing H/ACA snoRNAs. H/ACA sRNA and putative ORFs for H/ACA sRNP proteins (L7Ae, aCBF5, aNOP10 and aGAR1) were found in Archaea. Here, by using Pyrococcus abyssi recombinant proteins and an in vitro transcribed P.abyssi H/ACA sRNA, we obtained the first complete in vitro reconstitution of an active H/ACA RNP. Both L7Ae and the aCBF5 RNA:Psi synthase bind directly the sRNA; aCBF5 also interacts directly and independently with aNOP10 and aGAR1. Presence of aCBF5, aNOP10 and a U residue at the pseudouridylation site in the target RNA are required for RNA target recruitment. In agreement, we found that the aCBF5-aNOP10 pair is the minimal set of proteins needed for the formation of a particle active for pseudouridylation. However, particles more efficient in targeted pseudouridylation can be formed with the addition of proteins L7Ae and/or aGAR1. Although necessary for optimal activity, the conserved ACA motif in the sRNA was found to be not essential.
| S-EPMC1142404 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2014-06-19 | E-GEOD-52451 | biostudies-arrayexpress
Project description:H/ACA RNA-guided ribonucleoprotein particle (RNP), the most complicated RNA pseudouridylase so far known, uses H/ACA guide RNA for substrate capture and four proteins (Cbf5, Nop10, L7Ae and Gar1) for pseudouridylation. Although it was shown that Gar1 not only facilitates the product release, but also enhances the catalytic activity, the chemical role that Gar1 plays in this complicated machinery is largely unknown. Kinetics measurement on Pyrococcus furiosus RNPs at different temperatures making use of fluorescence anisotropy showed that Gar1 reduces the catalytic barrier through affecting the activation entropy instead of enthalpy. Site-directed mutagenesis combined with molecular dynamics simulations demonstrated that V149 in the thumb loop of Cbf5 is critical in placing the target uridine to the right position toward catalytic D85 of Cbf5. The enzyme elegantly aligns the position of uridine in the catalytic site with the help of Gar1. In addition, conversion of uridine to pseudouridine results in a rigid syn configuration of the target nucleotide in the active site and causes Gar1 to pull out the thumb. Both factors guarantee the efficient release of the product.
| S-EPMC4551948 | biostudies-literature
Project description:H/ACA ribonucleoproteins catalyse the sequence-dependent pseudouridylation of ribosomal and spliceosomal RNAs. Here, we reconstitute site-specifically fluorophore labelled H/ACA complexes and analyse their structural dynamics using single-molecule FRET spectroscopy. Our results show that the guide RNA is distorted into a substrate-binding competent conformation by specific protein interactions. Analysis of the reaction pathway using atomic mutagenesis establishes a new model how individual protein domains contribute to catalysis. Taken together, these results identify and characterize individual roles for all accessory proteins on the assembly and function of H/ACA RNPs.
| S-EPMC8354600 | biostudies-literature