Ribosomal RNA 2’-O-methylation dynamics during development and differentiation impact cell fate decisions.
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE199387 | GEO | 2023/06/15
REPOSITORIES: GEO
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Project description:Ribosomes, essential for the interpretation of genetic information, are not identical machineries without any control over the translation process. We and others have unveiled the natural diversity of ribosomes and how this impacts their function. One source of ribosome heterogeneity is the 2'-O-methylation (2'-O-me) of ribosomal RNA (rRNA). Here, we show that the rRNA 2'-O-me profile dynamically changes during mouse brain development and the directed differentiation of human embryonic stem cells (hESCs). Moreover, we demonstrate that the removal of one specific 2'-O-me, at position 28S:U3904, prompts hESCs to become early neural progenitor cells and favours hindbrain differentiation. Further analyses point towards an increased binding to FMRP and better translation of WNT pathway mRNAs by ribosomes devoid of 28S:U3904-me as the underlying mechanism for this identity shift.
2023-06-03 | GSE205022 | GEO
Project description:RNA methylations are essential both for RNA structure and function, and are introduced by a number of distinct methyltransferases (MTases). In recent years, N6-methyladenosine (m6A) modification of eukaryotic mRNA has been subject to intense studies, and it has been demonstrated that m6A is a reversible modification that regulates several aspects of mRNA function. However, m6A is also found in other RNAs, such as mammalian 18S and 28S ribosomal RNAs (rRNAs), but the responsible MTases have remained elusive. 28S rRNA carries a single m6A modification, found at position A4220 (alternatively referred to as A4190) within a stem-loop structure, and here we show that the MTase ZCCHC4 is the enzyme responsible for introducing this modification. Accordingly, we found that ZCCHC4 localises to nucleoli, the site of ribosome assembly, and that proteins involved in RNA metabolism are overrepresented in the ZCCHC4 interactome. Interestingly, the absence of m6A4220 perturbs codon-specific translation dynamics and shifts gene expression at the translational level. In summary, we establish ZCCHC4 as the enzyme responsible for m6A modification of human 28S rRNA, and demonstrate its functional significance in mRNA translation.
2019-11-25 | GSE128994 | GEO
Project description:H/ACA small nucleolar RNAs (snoRNAs) guide pseudouridylation as part of a small nucleolar ribonucleoprotein complex (snoRNP). Disruption of H/ACA snoRNA expression in stem cells impairs pluripotency, yet it remains unclear how H/ACA snoRNAs contribute to differentiation. To determine if H/ACA snoRNA expression is dynamic during differentiation, we comprehensively profiled H/ACA snoRNA expression in multiple murine cell types and during differentiation in three cellular models, including mouse embryonic stem cells and mouse myoblasts. We determined that H/ACA snoRNA expression is cell-type specific, and we identified a subset of snoRNAs that are specifically regulated during differentiation. Additionally, we demonstrated that a decrease in Snora27 expression upon differentiation corresponds to a decrease in pseudouridylation of its target site within the E-site transfer RNA (tRNA) binding region of the 28S ribosomal RNA (rRNA) in the large ribosomal subunit. Many of the snoRNAs regulated during differentiation have target nucleotides in the 28S rRNA, and we found that pre-rRNA processing of large subunit precursors is altered during differentiation. Together, these data suggest a model in which H/ACA snoRNAs are specifically regulated during differentiation to potentially alter pseudouridylation and fine tune ribosome function.
2020-07-09 | GSE140622 | GEO
Project description:H/ACA small nucleolar RNAs (snoRNAs) guide pseudouridylation as part of a small nucleolar ribonucleoprotein complex (snoRNP). Disruption of H/ACA snoRNA expression in stem cells impairs pluripotency, yet it remains unclear how H/ACA snoRNAs contribute to differentiation. To determine if H/ACA snoRNA expression is dynamic during differentiation, we comprehensively profiled H/ACA snoRNA expression in multiple murine cell types and during differentiation in three cellular models, including mouse embryonic stem cells and mouse myoblasts. We determined that H/ACA snoRNA expression is cell-type specific, and we identified a subset of snoRNAs that are specifically regulated during differentiation. Additionally, we demonstrated that a decrease in Snora27 expression upon differentiation corresponds to a decrease in pseudouridylation of its target site within the E-site transfer RNA (tRNA) binding region of the 28S ribosomal RNA (rRNA) in the large ribosomal subunit. Many of the snoRNAs regulated during differentiation have target nucleotides in the 28S rRNA, and we found that pre-rRNA processing of large subunit precursors is altered during differentiation. Together, these data suggest a model in which H/ACA snoRNAs are specifically regulated during differentiation to potentially alter pseudouridylation and fine tune ribosome function.
2020-07-09 | GSE140618 | GEO
Project description:The biogenesis of rRNA drives cell growth and proliferation, but mechanisms that modulate rRNA production remain poorly understood. We have conducted a genetic screen to look for factors that negatively regulate endo-siRNA generation in C. elegans, and identified the suppressor of siRNA (susi)-1and a new class of triphosphorylated antisense ribosomal siRNAs (risiRNAs). In susi-1 mutant, we observed an accumulation of siRNA sequences complementary to 18S and 26S rRNAs. risiRNAs are similar to 22G-RNA, as they are 22 nt in length and have a triphosphorylated guanidine at their 5'-end. The generation of risiRNAs depends on RNA-dependent RNA polymerases, but not the ERI/Dicer complex. risiRNAs act through the nuclear RNAi pathway and guide the Argonaute protein NRDE-3 to the nucleoli, which leads to a downregulation of pre-rRNA expression. Interestingly, low temperature and ultraviolet irradiation also induces the accumulation of risiRNA, suggesting potential regulatory functions. Cloned SUSI-1 shows homology to Dis3-like exonuclease 2 (Dis3L2) in other organisms, a gene identified as a key exonuclease involved in the 3' to 5' degradation of oligouridylated RNAs. We observed an accumulation of 3'-tail oligouridylated 26S rRNA in susi-1 mutant and in low temperature-treated animals. Consistently, the injection of 3'-tail oligouridylated 26S rRNA elicited a nuclear accumulation of NRDE-3. Our findings thus establish SUSI-1(ceDis3L2) as a suppressor of endo-siRNA generation, identify a novel class of risiRNAs that suppress pre-rRNA expression, and suggest a potential disease mechanism.
2016-12-07 | GSE90927 | GEO
Project description:Ribosomal RNAs (rRNAs) biogenesis are multistep processes requiring the activity of several nuclear and cytoplasmic exonucleases. The exact processing steps for mammalian 5.8S rRNA remains obscure. Here, using loss-of-function approaches in mouse embryonic stem cells and deep sequencing of rRNA intermediates, we investigate at nucleotide resolution the requirements of exonucleases known to be involved in 5.8S maturation, and explore the role of the Perlman syndrome-associated 3’-5’ exonuclease Dis3l2 in rRNA processing. We expand the repertoire of Dis3l2 targets to three 5.8S, 5S, and 28S rRNAs. We uncover a novel cytoplasmic intermediate that we name ‘7SB’ rRNA that is generated through sequential processing by distinct exosome complexes. 7SB rRNA can be oligouridylated by TUT4/7 and subsequently processed by Dis3l2 and Eri1. Moreover, exosome depletion triggers Dis3l2-mediated decay (DMD) as a surveillance pathway for rRNAs. Our data identify previously unknown 5.8S rRNA processing steps and provide nucleotide level insight into the exonuclease requirements for mammalian rRNA processing.
2019-04-13 | GSE129734 | GEO
Project description:H/ACA small nucleolar RNAs (snoRNAs) guide pseudouridylation as part of a small nucleolar ribonucleoprotein complex (snoRNP). Disruption of H/ACA snoRNA expression in stem cells impairs pluripotency, yet it remains unclear how H/ACA snoRNAs contribute to differentiation. To determine if H/ACA snoRNA expression is dynamic during differentiation, we comprehensively profiled H/ACA snoRNA expression in multiple murine cell types and during differentiation in three cellular models, including mouse embryonic stem cells and mouse myoblasts. We determined that H/ACA snoRNA expression is cell-type specific, and we identified a subset of snoRNAs that are specifically regulated during differentiation. Additionally, we demonstrated that a decrease in Snora27 expression upon differentiation corresponds to a decrease in pseudouridylation of its target site within the E-site transfer RNA (tRNA) binding region of the 28S ribosomal RNA (rRNA) in the large ribosomal subunit. Many of the snoRNAs regulated during differentiation have target nucleotides in the 28S rRNA, and we found that pre-rRNA processing of large subunit precursors is altered during differentiation. Together, these data suggest a model in which H/ACA snoRNAs are specifically regulated during differentiation to potentially alter pseudouridylation and fine tune ribosome function.
2020-07-09 | GSE139812 | GEO
Project description:Ribosome biogenesis is a multi-step process, during which mistakes could take place at any step of pre-rRNA processing, modification, and assembly of ribosomes. Misprocessed rRNAs are usually detected and degraded by surveillance machineries. Recently, we identified a class of antisense ribosomal siRNAs (risiRNAs) that downregulate pre-rRNAs through the nuclear RNAi pathway. To further understand the biological roles of risiRNA, we conducted both forward and reverse genetic screenings to search for more susi mutants. We isolated a number of genes that are broadly conserved from yeast to humans and are involved in pre-rRNA modification and processing. Among them, SUSI-2(ceRRP8) is homologous to human RRP8 and engages in m1A methylation of 26S rRNA. C27F2.4(ceBUD23) is a m7G methyltransferase of 18S rRNA. E02H1.1(ceDIMT1L) is a predicted m6(2)Am6(2)A methyltransferase of 18S rRNA . Mutation of these genes led to modification deficiency of rRNAs and elicited accumulation of risiRNAs, which further triggered the cytoplasm to nuclear and nucleolar translocation of an Argonaute protein NRDE-3. The processing deficiency of rRNAs resulted in the accumulation of risiRNAs as well. We isolated SUSI-3(RIOK-1) which is similar to human RIOK1 that cleaves 20S to 18S rRNA. We further utilized RNAi and CRISPR/Cas9 technologies to perform candidate-based reverse genetic screening and identified additional pre-rRNA processing factors that suppressed risiRNA production. Therefore, we concluded that erroneous rRNAs can trigger risiRNA generation and subsequently turn on the nuclear RNAi-mediated gene silencing pathway to inhibit pre-rRNA expression, which may provide a quality control mechanism to maintain the homeostasis of rRNAs.
2018-05-02 | GSE113905 | GEO
Project description:Epigenetic methyl-CpG silencing of the ribosomal RNA (rRNA) genes is thought to down-regulate rRNA synthesis in mammals. In contrast, we now show that CpG methylation in fact positively influences rRNA synthesis and processing. Human HCT116 cells, inactivated for DNMT1 and DNMT3b or treated with aza-dC, lack CpG methylation and reactivate a large fraction of normally silent rRNA genes. Unexpectedly, these cells display reduced rRNA synthesis and processing, and accumulate unprocessed 45S rRNA. Reactivation of the rRNA genes is associated with their cryptic transcription by RNA polymerase II. Ectopic expression of cryptic rRNA gene transcripts recapitulates the defects associated with loss of CpG methylation. The data demonstrate that rRNA gene silencing prevents cryptic RNA polymerase II transcription of these genes. Lack of silencing leads to the partial disruption of rRNA synthesis and rRNA processing, providing an unexpected explanation for the cytotoxic effects of loss of CpG methylation. Agilent custom microarray analyses of transcripts from sense and antisense strands of the human rRNA genes present in total nuclear RNA from HCT116-DNMT1-/-;DNMT3b-/- (DKO) and HCT116 (PS) cells. The DKO/PS RNA ratio was normalized within the 5â region of the 45S ribosomal RNA, since this sense coding region was found by quantitative Northern and S1-mapping analyses to equally present in the RNA pools from both cells (as compared to total RNA levels and 18S and 28S levels). The distribution for sense RNAs from the coding region is strongly influenced by the predominant RPI 45S rRNA transcript and hence peaks at 0, the DKO and PS 45S rRNA signals having been normalized. 60-mer probes were designed to tile Human rDNA (GenBank accession U13369) on both strands using ArrayOligoSelector (Wardle et al., 2006). A total of 1,146 different non-overlapping probes (573 for each DNA strand) were designed to cover the 43 kb of human rDNA and each printed in triplicate on the array. The experiment was performed using a dye-swap duplicate analysis. The microarrays were scanned on a G2565CA DNA microarray scanner (Agilent Technologies) and the quantification performed using the Feature Extraction software (Agilent technologies). The data were analyzed using the LIMMA software package in R (Smyth and Speed, 2003).
2010-05-16 | E-GEOD-17042 | biostudies-arrayexpress
Project description:Epigenetic methyl-CpG silencing of the ribosomal RNA (rRNA) genes is thought to down-regulate rRNA synthesis in mammals. In contrast, we now show that CpG methylation in fact positively influences rRNA synthesis and processing. Human HCT116 cells, inactivated for DNMT1 and DNMT3b or treated with aza-dC, lack CpG methylation and reactivate a large fraction of normally silent rRNA genes. Unexpectedly, these cells display reduced rRNA synthesis and processing, and accumulate unprocessed 45S rRNA. Reactivation of the rRNA genes is associated with their cryptic transcription by RNA polymerase II. Ectopic expression of cryptic rRNA gene transcripts recapitulates the defects associated with loss of CpG methylation. The data demonstrate that rRNA gene silencing prevents cryptic RNA polymerase II transcription of these genes. Lack of silencing leads to the partial disruption of rRNA synthesis and rRNA processing, providing an unexpected explanation for the cytotoxic effects of loss of CpG methylation. Agilent custom microarray analyses of transcripts from sense and antisense strands of the human rRNA genes present in total nuclear RNA from HCT116-DNMT1-/-;DNMT3b-/- (DKO) and HCT116 (PS) cells. The DKO/PS RNA ratio was normalized within the 5’ region of the 45S ribosomal RNA, since this sense coding region was found by quantitative Northern and S1-mapping analyses to equally present in the RNA pools from both cells (as compared to total RNA levels and 18S and 28S levels). The distribution for sense RNAs from the coding region is strongly influenced by the predominant RPI 45S rRNA transcript and hence peaks at 0, the DKO and PS 45S rRNA signals having been normalized.
2009-07-11 | GSE17042 | GEO