Nopp140-chaperoned 2’-O-methylation of small nuclear RNAs in Cajal bodies ensures splicing fidelity
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PROVIDER: PRJNA724033 | ENA |
REPOSITORIES: ENA
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Project description:Spliceosomal small nuclear RNAs (snRNAs) are modified by small Cajal body (CB) specific ribonucleoproteins (scaRNPs) to ensure snRNP biogenesis and pre-mRNA splicing. However, the function and subcellular site of snRNA modification are largely unknown. We show that CB localization of the protein Nopp140 is essential for concentration of scaRNPs in that nuclear condensate; and that phosphorylation by casein kinase 2 (CK2) at some 80 serines targets Nopp140 to CBs. Transiting through CBs, snRNAs are apparently modified by scaRNPs. Indeed, Nopp140 knockdown-mediated release of scaRNPs from CBs severely compromises 2’-O-methylation of spliceosomal snRNAs, identifying CBs as the site of scaRNP catalysis. Additionally, alternative splicing patterns change indicating that these modifications in U1, U2, U5, and U12 snRNAs safeguard splicing fidelity. Given the importance of CK2 in this pathway, compromised splicing could underlie the mode of action of small molecule CK2 inhibitors currently considered for therapy in cholangiocarcinoma, hematological malignancies, and COVID-19.
2021-07-01 | GSE173171 | GEO
Project description: Not available
| S-EPMC8336889 | biostudies-literature
Project description:Cajal bodies are linked to genome conformation
| PRJNA312097 | ENA
Project description:The mechanisms underlying nuclear body (NB) formation and their contribution to genome function are unknown. We examined the non-random positioning of Cajal bodies (CBs), major NBs involved in spliceosomal snRNP assembly, and their role in genome organization. CBs are predominantly located at the periphery of chromosome territories at a multi-chromosome interface. Genome-wide chromatin conformation capture analysis (4C-seq) using CB-interacting loci revealed that CB-associated regions are enriched with highly expressed histone genes and U small nuclear and nucleoar RNA (sn/snoRNA) loci that form intra- and inter-chromosomal clusters. We observed a number of CB-dependent gene positioning events on chromosome 1. RNAi-mediated disassembly of CBs disrupts the CB-targeting gene clusters and suppresses the expression of U sn/snoRNA and histone genes. This loss of spliceosomal snRNP production resulted in increased splicing noise, even in CB-distal regions. We conclude that CBs contribute to genome organization with global effects on gene expression and RNA splicing fidelity.
2016-03-21 | GSE77913 | GEO
Project description:The mechanisms underlying nuclear body (NB) formation and their contribution to genome function are unknown. We examined the non-random positioning of Cajal bodies (CBs), major NBs involved in spliceosomal snRNP assembly, and their role in genome organization. CBs are predominantly located at the periphery of chromosome territories at a multi-chromosome interface. Genome-wide chromatin conformation capture analysis (4C-seq) using CB-interacting loci revealed that CB-associated regions are enriched with highly expressed histone genes and U small nuclear and nucleoar RNA (sn/snoRNA) loci that form intra- and inter-chromosomal clusters. We observed a number of CB-dependent gene positioning events on chromosome 1. RNAi-mediated disassembly of CBs disrupts the CB-targeting gene clusters and suppresses the expression of U sn/snoRNA and histone genes. This loss of spliceosomal snRNP production resulted in increased splicing noise, even in CB-distal regions. We conclude that CBs contribute to genome organization with global effects on gene expression and RNA splicing fidelity.
2016-03-21 | GSE77915 | GEO
Project description:The mechanisms underlying nuclear body (NB) formation and their contribution to genome function are unknown. We examined the non-random positioning of Cajal bodies (CBs), major NBs involved in spliceosomal snRNP assembly, and their role in genome organization. CBs are predominantly located at the periphery of chromosome territories at a multi-chromosome interface. Genome-wide chromatin conformation capture analysis (4C-seq) using CB-interacting loci revealed that CB-associated regions are enriched with highly expressed histone genes and U small nuclear and nucleoar RNA (sn/snoRNA) loci that form intra- and inter-chromosomal clusters. We observed a number of CB-dependent gene positioning events on chromosome 1. RNAi-mediated disassembly of CBs disrupts the CB-targeting gene clusters and suppresses the expression of U sn/snoRNA and histone genes. This loss of spliceosomal snRNP production resulted in increased splicing noise, even in CB-distal regions. We conclude that CBs contribute to genome organization with global effects on gene expression and RNA splicing fidelity.
2016-03-21 | GSE77914 | GEO
Project description:Chd4 ensures stem cell lineage fidelity during skeletal muscle regeneration
| PRJNA744544 | ENA
Project description:The non-polyadenylated mRNAs of replication-dependent histones (RDHs) and small nuclear RNAs (snRNAs) are synthesized by RNA polymerase II at histone locus bodies (HLBs) and Cajal bodies (CBs), respectively. We previously showed that MED26-containing Mediator regulates the 3'-end processing of non-polyadenylated transcripts by recruiting Little Elongation Complex (LEC) to the genes. HLBs frequently associate with CBs, in which 3'-end processing factors for RDH genes are enriched; however, this association’s role has not been elucidated. Here, we show that disruption of the Mediator docking site for LEC by mutating the MED26-binding site of EAF1, a subunit of LEC, interferes with CBs’ association with HLBs, resulting in decreased inter-chromosome interaction between RDH gene clusters and increased aberrant unprocessed RDH gene transcripts. Our findings suggest a model in which LEC recruitment by Mediator plays a role in CBs’ association with HLBs to facilitate the 3'-end processing of RDH genes by supplying 3'-end processing factors.
2022-04-26 | GSE164144 | GEO
Project description:Splicing is catalyzed by the spliceosome, a compositionally dynamic complex assembled stepwise on pre-mRNA. We reveal links between splicing machinery components and the intrinsically disordered ciliopathy protein SANS. Pathogenic mutations in SANS/USH1G lead to Usher syndrome––the most common cause of deaf-blindness. Previously, SANS was shown to function only in the cytosol and primary cilia. Here, we have uncovered molecular links between SANS and pre-mRNA splicing catalyzed by the spliceosome in the nucleus. We show that SANS is found in Cajal bodies and nuclear speckles, where it interacts with components of spliceosomal subcomplexes such as SF3B1 and the large splicing cofactor SON but also with PRPFs and snRNAs related to the tri-snRNP complex. SANS is required for the transfer of tri-snRNPs between Cajal bodies and nuclear speckles for spliceosome assembly and may also participate in snRNP recycling back to Cajal bodies. SANS depletion alters the kinetics of spliceosome assembly, leading to accumulation of complex A. SANS deficiency and USH1G pathogenic mutations affects splicing of genes related to cell proliferation and USH. Thus, we provide the first evidence that splicing dysregulation may participate in the pathophysiology of Usher syndrome.
2021-05-25 | PXD023942 | Pride
Project description:The 3' Pol II pausing at replication-dependent histone genes is regulated by Mediator through Cajal bodies’ association with histone locus bodies
| PRJNA689216 | ENA