JANUS, a spliceosome-associated protein, promotes miRNA biogenesis in Arabidopsis
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ABSTRACT:
PROVIDER: PRJNA954823 | ENA |
REPOSITORIES: ENA
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Project description:MicroRNAs (miRNAs) are important regulators of gene expression. Their levels are precisely controlled through modulating the activity of the microprocesser complex (MC). Here we report that JANUS, a homology of the conserved U2 snRNP assembly factor in yeast and human, is required for miRNA accumulation. JANUS associates with MC components Dicer-like 1 and SERRATE (SE) and directly binds the stem-loop of pri-miRNAs. In a hypomorphic janus mutant, the activity of DCL1, the numbers of MC, and the interaction of primary miRNA transcript (pri-miRNAs) with MC are reduced. These data suggest that JANUS promotes the assembly and activity of MC through its interaction with MC and/or pri-miRNAs. In addition, JANUS modulates the transcription of some pri-miRNAs as it binds the promoter of pri-miRNAs and promotes Pol II occupancy of at their promoters. Moreover, global splicing defects are detected in janus. Taken together, our study reveals a novel role of a conserved splicing factor in miRNA biogenesis.
2023-06-01 | GSE229519 | GEO
Project description:MicroRNAs (miRNAs) are important regulators of genes expression. Their levels are precisely controlled through modulating the activity of the microprocesser complex (MC). Here, we report that JANUS, a homology of the conserved U2 snRNP assembly factor in yeast and human, is required for miRNA accumulation. JANUS associates with MC components Dicer-like 1 (DCL1) and SERRATE (SE) and directly binds the stem-loop of pri-miRNAs. In a hypomorphic janus mutant, the activity of DCL1, the numbers of MC, and the interaction of primary miRNA transcript (pri-miRNAs) with MC are reduced. These data suggest that JANUS promotes the assembly and activity of MC through its interaction with MC and/or pri-miRNAs. In addition, JANUS modulates the transcription of some pri-miRNAs as it binds the promoter of pri-miRNAs and facilitates Pol II occupancy of at their promoters. Moreover, global splicing defects are detected in janus. Taken together, our study reveals a novel role of a conserved splicing factor in miRNA biogenesis.
| S-EPMC10783502 | biostudies-literature
Project description:A battery of spliceosome-associated proteins has been identified in microRNA (miRNA) biogenesis; however, the underlying mechanisms remain elusive. The intron lariat spliceosome (ILS) complex is highly conserved among eukaryotes and its disassembly marks the end of a canonical splicing cycle. In this study, we show that two conserved disassembly factors of the ILS complex, ILP1 and NTR1, positively regulate microRNA biogenesis through facilitating transcriptional elongation in Arabidopsis. ILP1 and NTR1 form a stable complex and co-regulate alternative splicing of more than a hundred genes across the genome including the core circadian gene LHY and some pri-miRNAs. Dysfunction in either ILP1 or NTR1 result in reduced RNA polymerase II occupancy at elongated regions of MIR chromatins, without affecting MIR promoter activity, pri-miRNA decay and DCL1 processing. Our results provide insights into the molecular mechanisms of spliceosomal machineries in non-coding RNA regulation.
2019-11-12 | PXD011542 | Pride
Project description:XPO5 is required for miRNA biogenesis and promotes primary miRNA processing independent of RanGTP
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Project description:The intron-lariat spliceosome (ILS) complex is highly conserved among eukaryotes, and its disassembly marks the end of a canonical splicing cycle. In this study, we show that two conserved disassembly factors of the ILS complex, Increased Level of Polyploidy1-1D (ILP1) and NTC-Related protein 1 (NTR1), positively regulate microRNA (miRNA) biogenesis by facilitating transcriptional elongation of MIRNA (MIR) genes in Arabidopsis thaliana. ILP1 and NTR1 formed a stable complex and co-regulated alternative splicing of more than a hundred genes across the Arabidopsis genome, including some primary transcripts of miRNAs (pri-miRNAs). Intriguingly, pri-miRNAs, regardless of having introns or not, were globally down-regulated when the ILP1 or NTR1 function was compromised. ILP1 and NTR1 interacted with core miRNA processing proteins Dicer-like 1 and Serrate, and were required for proper RNA polymerase II occupancy at elongated regions of MIR chromatin, without affecting either MIR promoter activity or pri-miRNA decay. Our results provide further insights into the regulatory role of spliceosomal machineries in the biogenesis of miRNAs.
| S-EPMC6736097 | biostudies-literature
Project description:The studies of spliceosomal interactions are challenging due to their dynamic nature. Here we developed spliceosome iCLIP, which immunoprecipitates SmB along with snRNPs and auxiliary RNA binding proteins (RBPs) to simultaneously map the spliceosomal binding to human snRNAs and pre-mRNAs. This identified 9 distinct regions on pre-mRNAs, which overlap with position-dependent binding patterns of 15 RBPs. Using spliceosome iCLIP, we additionally identified >50,000 branchpoints (BPs) that have canonical features, unlike those identified by RNA-seq. The iCLIP BPs generally overlap with the computationally predicted BPs, and alternative BPs are associated with extended regions of structurally accessible RNA. We find that the position and strength of BPs defines the binding patterns of SF3 and U2AF complexes, whereas the RNA structure around BPs affects the sensitivity of exons to perturbation of these complexes. Our findings introduce spliceosome iCLIP as a new method for transcriptomic studies of BPs and splicing mechanisms.
2019-08-30 | E-MTAB-6950 | biostudies-arrayexpress
Project description:MicroRNAs (miRNAs) play crucial roles in gene expression regulation through RNA cleavage or translation repression. Here, we report the identification of an evolutionarily conserved WD40 domain protein as a player in miRNA biogenesis in Arabidopsis thaliana. A mutation in the REDUCTION IN BLEACHED VEIN AREA (RBV) gene encoding a WD40 domain protein led to the suppression of leaf bleaching caused by an artificial miRNA; the mutation also led to a global reduction in the accumulation of endogenous miRNAs. The nuclear protein RBV promotes the transcription of MIR genes into pri-miRNAs by enhancing the occupancy of RNA polymerase II (Pol II) at MIR gene promoters. RBV also promotes the loading of miRNAs into AGO1. In addition, RNA-seq revealed a global splicing defect in the mutant. Thus, this evolutionarily conserved, nuclear WD40 domain protein acts in miRNA biogenesis and RNA splicing.
2022-02-26 | GSE152910 | GEO