Arabidopsis MOS4-associated complex promotes microRNA biogenesis and pre-mRNA splicing
Ontology highlight
ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE103423 | GEO | 2017/12/06
SECONDARY ACCESSION(S): PRJNA401314
REPOSITORIES: GEO
Similar Datasets
Project description:The evolutionarily conserved, putative RNA helicase MAC7 exists in both animals and plants. The human MAC7 homolog, Aquarius, is part of the spliceosome and plays a role in pre-mRNA splicing in vitro. In Arabidopsis, MAC7 was shown to be part of the MOS4-associated complex (MAC), which is required for plant defense and development. Here through RNA-seq analysis we discover that down-regulated genes in MAC subunit mutants are mostly involved in plant defense and stimulus response, confirming a role of MAC in the regulation of biotic and abiotic stress responses. We also discover global intron retention defects in mutants in three members of MAC, thus linking the functions of MAC to splicing in Arabidopsis. In addition, we show that mac7-1, a partial loss-of-function mutant in MAC7, and two other MAC subunit mutants, mac3a mac3b and prl1 prl2, exhibit reduced microRNA levels in general, indicating that MAC promotes microRNA biogenesis. The mac7-1 mutant shows reduced primary miRNA (pri-miRNA) levels without affecting MIR promoter activity or the degradation of pri-miRNA transcripts, implicating functions of MAC7 during transcription elongation or maturation of pri-miRNAs. As a nuclear protein, MAC7 is not localized in dicing bodies, but it affects the localization of HYL1 to dicing bodies. We propose that MAC acts to link MIR transcription to pri-miRNA processing.
2017-12-08 | GSE103422 | GEO
Project description:The evolutionarily conserved, putative RNA helicase MAC7 exists in both animals and plants. The human MAC7 homolog, Aquarius, is part of the spliceosome and plays a role in pre-mRNA splicing in vitro. In Arabidopsis, MAC7 was shown to be part of the MOS4-associated complex (MAC), which is required for plant defense and development. Here through RNA-seq analysis we discover that down-regulated genes in MAC subunit mutants are mostly involved in plant defense and stimulus response, confirming a role of MAC in the regulation of biotic and abiotic stress responses. We also discover global intron retention defects in mutants in three members of MAC, thus linking the functions of MAC to splicing in Arabidopsis. In addition, we show that mac7-1, a partial loss-of-function mutant in MAC7, and two other MAC subunit mutants, mac3a mac3b and prl1 prl2, exhibit reduced microRNA levels in general, indicating that MAC promotes microRNA biogenesis. The mac7-1 mutant shows reduced primary miRNA (pri-miRNA) levels without affecting MIR promoter activity or the degradation of pri-miRNA transcripts, implicating functions of MAC7 during transcription elongation or maturation of pri-miRNAs. As a nuclear protein, MAC7 is not localized in dicing bodies, but it affects the localization of HYL1 to dicing bodies. We propose that MAC acts to link MIR transcription to pri-miRNA processing.
2017-12-08 | GSE98035 | GEO
Project description:Arabidopsis MOS4-associated complex promotes microRNA biogenesis and pre-mRNA splicing
| PRJNA401314 | ENA
Project description:MicroRNAs (miRNAs) are central regulators of gene expression, and a large fraction of them are encoded in introns of RNA polymerase II transcripts. Thus, the biogenesis of intronic miRNAs by the microprocessor and the splicing of their host introns by the spliceosome require coordination between these processing events. This cross-talk is addressed here. We show that key microprocessor proteins Drosha and DGCR8 as well as pre-miRNAs cosediment with supraspliceosomes, where nuclear posttranscriptional processing is executed. We further show that inhibition of splicing increases miRNAs expression, whereas knock-down of Drosha increases splicing. We identified a novel splicing event in intron 13 of MCM7, where the miR-106b-25 cluster is located. The unique splice isoform includes a hosted pre-miRNA in the extended exon and excludes its processing. This indicates a possible mechanism of altering the levels of different miRNAs originating from the same transcript. Altogether, our study indicates interplay between the splicing and microprocessor machineries within a supraspliceosome context.
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Project description:The processing of Arabidopsis thaliana microRNAs (miRNAs) from longer primary transcripts (pri-miRNAs) requires the activity of several proteins, including DICER-LIKE1 (DCL1), the double-stranded RNA-binding protein HYPONASTIC LEAVES1 (HYL1), and the zinc finger protein SERRATE (SE). It has been noted before that the morphological appearance of weak se mutants is reminiscent of plants with mutations in ABH1/CBP80 and CBP20, which encode the two subunits of the nuclear cap-binding complex. We report that, like SE, the cap-binding complex is necessary for proper processing of pri-miRNAs. Inactivation of either ABH1/CBP80 or CBP20 results in decreased levels of mature miRNAs accompanied by apparent stabilization of pri-miRNAs. Whole-genome tiling array analyses reveal that se, abh1/cbp80, and cbp20 mutants also share similar splicing defects, leading to the accumulation of many partially spliced transcripts. This is unlikely to be an indirect consequence of improper miRNA processing or other mRNA turnover pathways, because introns retained in se, abh1/cbp80, and cbp20 mutants are not affected by mutations in other genes required for miRNA processing or for nonsense-mediated mRNA decay. Taken together, our results uncover dual roles in splicing and miRNA processing that distinguish SE and the cap-binding complex from specialized miRNA processing factors such as DCL1 and HYL1.
| S-EPMC2426964 | biostudies-literature
Project description:Light signals regulate plant growth and development by controlling a plethora of gene expression changes. Posttranscriptional regulation, especially pre-mRNA processing, is a key modulator of gene expression; however, the molecular mechanisms linking pre-mRNA processing and light signaling are not well understood. Here we report a protein related to the human splicing factor 45 (SPF45) named splicing factor for phytochrome signaling (SFPS), which directly interacts with the photoreceptor phytochrome B (phyB). In response to light, SFPS-RFP (red fluorescent protein) colocalizes with phyB-GFP in photobodies. sfps loss-of-function plants are hyposensitive to red, far-red, and blue light, and flower precociously. SFPS colocalizes with U2 small nuclear ribonucleoprotein-associated factors including U2AF65B, U2A', and U2AF35A in nuclear speckles, suggesting SFPS might be involved in the 3' splice site determination. SFPS regulates pre-mRNA splicing of a large number of genes, of which many are involved in regulating light signaling, photosynthesis, and the circadian clock under both dark and light conditions. In vivo RNA immunoprecipitation (RIP) assays revealed that SFPS associates with EARLY FLOWERING 3 (ELF3) mRNA, a critical link between light signaling and the circadian clock. Moreover, PHYTOCHROME INTERACTING FACTORS (PIFs) transcription factor genes act downstream of SFPS, as the quadruple pif mutant pifq suppresses defects of sfps mutants. Taken together, these data strongly suggest SFPS modulates light-regulated developmental processes by controlling pre-mRNA splicing of light signaling and circadian clock genes.
| S-EPMC5565451 | biostudies-literature
Project description:Both microRNAs and alternative pre-mRNA splicing have been implicated in the development of the nervous system (NS), but functional interactions between these two pathways are poorly understood. We demonstrate that the neuron-specific microRNA miR-124 directly targets PTBP1 (PTB/hnRNP I) mRNA, which encodes a global repressor of alternative pre-mRNA splicing in nonneuronal cells. Among the targets of PTBP1 is a critical cassette exon in the pre-mRNA of PTBP2 (nPTB/brPTB/PTBLP), an NS-enriched PTBP1 homolog. When this exon is skipped, PTBP2 mRNA is subject to nonsense-mediated decay (NMD). During neuronal differentiation, miR-124 reduces PTBP1 levels, leading to the accumulation of correctly spliced PTBP2 mRNA and a dramatic increase in PTBP2 protein. These events culminate in the transition from non-NS to NS-specific alternative splicing patterns. We also present evidence that miR-124 plays a key role in the differentiation of progenitor cells to mature neurons. Thus, miR-124 promotes NS development, at least in part by regulating an intricate network of NS-specific alternative splicing.
| S-EPMC3139456 | biostudies-literature
Project description:TRAP150 has been identified as a subunit of the transcription regulatory complex TRAP/Mediator, and also a component of the spliceosome. The exact function of TRAP150, however, remains unclear. We recently identified TRAP150 by its association with the mRNA export factor TAP. TRAP150 contains an arginine/serine-rich domain and has sequence similarity with the cell death-promoting transcriptional repressor BCLAF1. We found that TRAP150 co-localizes with splicing factors in nuclear speckles, and is required for pre-mRNA splicing and activates splicing in vivo. TRAP150 remains associated with the spliced mRNA after splicing, and accordingly, it interacts with the integral exon junction complex. Unexpectedly, when tethered to a precursor mRNA, TRAP150 can trigger mRNA degradation in the nucleus. However, unlike nonsense-mediated decay, TRAP150-mediated mRNA decay is irrespective of the presence of upstream stop codons and occurs in the nucleus. Moreover, TRAP150 activates pre-mRNA splicing and induces mRNA degradation by its separable functional domains. Therefore, TRAP150 represents a multi-functional protein involved in nuclear mRNA metabolism.
| S-EPMC2879504 | biostudies-other
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2016-09-06 | E-GEOD-76134 | biostudies-arrayexpress
Project description:Most unwanted RNA transcripts in the nucleus of eukaryotic cells, such as splicing-defective pre-mRNAs and spliced-out introns, are rapidly degraded by the nuclear exosome. In budding yeast, a number of these unwanted RNA transcripts, including spliced-out introns, are first recognized by the nuclear exosome cofactor Trf4/5p-Air1/2p-Mtr4p polyadenylation (TRAMP) complex before subsequent nuclear-exosome-mediated degradation. However, it remains unclear when spliced-out introns are recognized by TRAMP, and whether TRAMP may have any potential roles in pre-mRNA splicing. Here, we demonstrated that TRAMP is cotranscriptionally recruited to nascent RNA transcripts, with particular enrichment at intronic sequences. Deletion of TRAMP components led to further accumulation of unspliced pre-mRNAs even in a yeast strain defective in nuclear exosome activity, suggesting a novel stimulatory role of TRAMP in splicing. We also uncovered new genetic and physical interactions between TRAMP and several splicing factors, and further showed that TRAMP is required for optimal recruitment of the splicing factor Msl5p. Our study provided the first evidence that TRAMP facilitates pre-mRNA splicing, and we interpreted this as a fail-safe mechanism to ensure the cotranscriptional recruitment of TRAMP before or during splicing to prepare for the subsequent targeting of spliced-out introns to rapid degradation by the nuclear exosome.
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