Project description:Two Arabidopsis thaliana splicing factor [AtU2AF65 isoforms (AtU2AF65a and AtU2AF65b)] mutants displayed the opposite flowering phenotypes. To assay the RNA processing including alternative splicing and pre-mRNA splicing of target genes of this protein in Arabidopsis, the 7-day seedlings (shoot apices) of wild type atu2af65a and atu2af65b mutants were used for RNA-Seq.
Project description:Alternative splicing is prevalent in plants, but little is known about its regulation in the context of developmental and signaling pathways. We describe here a new factor that influences pre-mRNA splicing and is essential for embryonic development in Arabidopsis thaliana. This factor was retrieved in a genetic screen that identified mutants impaired in expression of an alternatively spliced GFP reporter gene. In addition to the known spliceosomal component PRP8, the screen retrieved a previously uncharacterized protein containing a Replication termination factor2 (Rtf2) domain defined by a C2HC2 zinc finger. The Rtf2 protein was discovered in fission yeast, where it stabilizes paused DNA replication forks by an unknown mechanism. When homozygous, a null mutation in Arabidopsis RTF2 (AtRTF2) is embryo-lethal, indicating that it encodes an essential protein. As revealed by quantitative RT-PCR, impaired expression of GFP in atrtf2 and prp8 mutants is attributable to inefficient splicing of the GFP pre-mRNA. A genome-wide analysis using RNA-seq demonstrated that 12% of total introns display a significant degree of retention in atrtf2 mutants. Intron-retaining transcripts are enriched from genes encoding proteins involved in signaling pathways and membrane transport. Affinity purification of AtRTF2 followed by mass spectrometry identified several known and predicted splicing proteins. In a yeast two-hybrid screen, AtRTF2 interacted with Exo70B1, a peripheral subunit of the exocyst, which is involved in vesicle trafficking. Considering these results and previous suggestions that Rtf2 constitutes an ubiquitin-related domain, we discuss possible roles of AtRTF2 in ubiquitin-based regulation of pre-mRNA splicing and membrane signaling to the spliceosome. Rtf2 is SDR1 (= AtRTF2) and was discovered in a genetic suppressor screen using the dms4 mutant. DMS4 was described in Kanno et al (2010) EMBO Rep. 11:65-71. Examination of whole-genome DNA methylation status in transgenic Arabidopsis plants
Project description:The homozygous of mutants of Arabidopsis gene (AT1G60900) are early flower. This gene encodes a homolog of yeast U2AF65 which is involved in pre-mRNA splicing of target genes. To assay the introns characters of target genes of this protein in Arabidopsis thaliana, the 10-day seedlings of wild type and atu2af65b mutant were used for RNA-Seq.
Project description:Alternative splicing is prevalent in plants, but little is known about its regulation in the context of developmental and signaling pathways. We describe here a new factor that influences pre-mRNA splicing and is essential for embryonic development in Arabidopsis thaliana. This factor was retrieved in a genetic screen that identified mutants impaired in expression of an alternatively spliced GFP reporter gene. In addition to the known spliceosomal component PRP8, the screen retrieved a previously uncharacterized protein containing a Replication termination factor2 (Rtf2) domain defined by a C2HC2 zinc finger. The Rtf2 protein was discovered in fission yeast, where it stabilizes paused DNA replication forks by an unknown mechanism. When homozygous, a null mutation in Arabidopsis RTF2 (AtRTF2) is embryo-lethal, indicating that it encodes an essential protein. As revealed by quantitative RT-PCR, impaired expression of GFP in atrtf2 and prp8 mutants is attributable to inefficient splicing of the GFP pre-mRNA. A genome-wide analysis using RNA-seq demonstrated that 12% of total introns display a significant degree of retention in atrtf2 mutants. Intron-retaining transcripts are enriched from genes encoding proteins involved in signaling pathways and membrane transport. Affinity purification of AtRTF2 followed by mass spectrometry identified several known and predicted splicing proteins. In a yeast two-hybrid screen, AtRTF2 interacted with Exo70B1, a peripheral subunit of the exocyst, which is involved in vesicle trafficking. Considering these results and previous suggestions that Rtf2 constitutes an ubiquitin-related domain, we discuss possible roles of AtRTF2 in ubiquitin-based regulation of pre-mRNA splicing and membrane signaling to the spliceosome. Rtf2 is SDR1 (= AtRTF2) and was discovered in a genetic suppressor screen using the dms4 mutant. DMS4 was described in Kanno et al (2010) EMBO Rep. 11:65-71.
Project description:Human genome encodes nine protein arginine methyltransferases (PRMT1–9), which catalyze three types of arginine methylation: monomethylation (MMA), asymmetric dimethylation (ADMA), and symmetric dimethylation (SDMA). These modifications can alter protein-protein and protein-nucleic acid interactions and play critical roles in transcription regulation and RNA metabolism. A few years ago, we characterized the newest member of the PRMT family–PRMT9 as a SDMA modifying enzyme and identified the splicing factor SF3B2 as its methylation substrate, linking its function to pre-mRNA splicing. However, the biological function of PRMT9 and the molecular mechanism by which PRMT9-catalyzed SF3B2 arginine methylation regulates pre-mRNA splicing remain largely unknown. Here, by charactering an intellectual disability patient-derived PRMT9 mutation (G189R) and establishing a Prmt9 conditional knockout (cKO) mouse model, we uncovered an important function of PRMT9 in neuronal development. We found that G189R mutation completely abolishes PRMT9 methyltransferase activity and destabilizes the protein by promoting its ubiquitination and proteasome degradation. PRMT9 loss in hippocampal neurons alters RNA splicing of ~1800 transcripts, which likely account for the abnormal synapse development and impaired learning and memory observed in the Prmt9 cKO mouse. Mechanistically, we discovered a critical protein-RNA interaction between the arginine 508 (R508) of SF3B2, the site that is exclusively methylated by PRMT9, and the pre-mRNA anchoring site, a cis-regulatory element located upstream of the branch point sequence (BPS). Additionally, we provide strong evidence that supports SF3B2 being the major and likely only substrate of PRMT9, thus highlighting the conserved function of PRMT9/SF3B2 axis in pre-mRNA splicing regulation.
Project description:In this study, we analyzed the Arabidopsis homologue of PRMT5, AtPRMT5’s function in RNA processing. RNA-seq analyses revealed that AtPRMT5 is involved in a subset of pre-mRNA splicing. Several RNA processing factors involved in regulating flowering time were validated that the corresponding intron retention surely exists in atprmt5 mutants. AtSm proteins can also be methylated by AtPRMT5 in vitro and in vivo, which may be the reasons for the pre-mRNA splicing defects in atprmt5. Contributed by The Institute of Genetics and Developmental Biology (IGDB) of the Chinese Academy of Sciences
Project description:We identified PRP4 kinase-A (PRP4ka) in a forward genetic screen based on an alternatively-spliced GFP reporter gene in Arabidopsis thaliana (Arabidopsis). Prp4 kinase, which was the first spliceosome-associated kinase shown to regulate splicing in fungi and mammals, has not yet been studied in plants. Analysis of RNA-seq data from the prp4ka mutant revealed widespread perturbations in alternative splicing. A quantitative iTRAQ-based phosphoproteomics investigation of the mutant identified phosphorylation changes in several serine/arginine-rich proteins, which regulate constitutive and alternative splicing, as well as other splicing-related factors. The results demonstrate the importance of PRP4ka in alternative splicing and suggest that PRP4ka may influence alternative splicing patterns by phosphorylating a subset of splicing regulators.
Project description:In this study, we analyzed the Arabidopsis homologue of PRMT5, AtPRMT5M-bM-^@M-^Ys function in RNA processing. RNA-seq analyses revealed that AtPRMT5 is involved in a subset of pre-mRNA splicing. Several RNA processing factors involved in regulating flowering time were validated that the corresponding intron retention surely exists in atprmt5 mutants. AtSm proteins can also be methylated by AtPRMT5 in vitro and in vivo, which may be the reasons for the pre-mRNA splicing defects in atprmt5. Contributed by The Institute of Genetics and Developmental Biology (IGDB) of the Chinese Academy of Sciences Investigate the role of AtPRMT5 in pre-mRNA splicing
Project description:Study on differential gene expression and splicing between wildtype and clock mutants. This study is part of a comparative analysis of the role of Protein Methyltransferase 5 in the regulation of transcriptional and post-transcriptional processes simultaneously in Arabidopsis and Drosophila. Circadian rhythms allow organisms to time biological processes to the most appropriate phases of the day/night cycle1. Post-transcriptional regulation is emerging as an important component of circadian networks2-6, but the molecular mechanisms linking the circadian clock to the control of RNA processing are largely unknown. Here we show that Protein Arginine Methyl Transferase 5 (PRMT5), which transfers methyl groups to arginine residues present in histones7 and Sm spliceosomal proteins8,9, links the circadian clock to the control of alternative splicing in plants. Mutations in prmt5impair multiple circadian rhythms in Arabidopsis thaliana and this phenotype is caused, at least in part, by a strong alteration in alternative splicing of the core-clock gene PSEUDO RESPONSE REGULATOR 9 (PRR9). Furthermore, genome wide studies show that PRMT5 contributes to regulate many pre-mRNA splicing events most likely modulating 5´splice site (5´ss) recognition. PRMT5 expression shows daily and circadian oscillations, and this contributes to mediate the circadian regulation of expression and alternative splicing of a subset of genes. Circadian rhythms in locomotor activity are also disrupted in dart5, a mutant affected in the Drosophila melanogaster PRMT5 homolog, and this is associated with alterations in splicing of the core-clock gene period (per) and several clock associated genes. Our results reveal a key role for PRMT5 in the regulation of alternative splicing and indicate that the interplay between the circadian clock and the regulation of alternative splicing by PRMT5 constitutes a common mechanism that helps organisms to synchronize physiological processes with daily changes in environmental conditions.