MRNA-seq data of 14 days old Arabidopsis seedlings in Col-0 and At rz-1b At rz-1c double mutant
Ontology highlight
ABSTRACT: Nuclear-localized RNA binding proteins are involved in various aspects of RNA metabolism, which in turn modulates gene expression. However, the functions of nuclear-localized RNA binding proteins in plants are poorly understood. Here we report the functions of two proteins containing RNA recognition motifs, At RZ-1B and At RZ-1C, in Arabidopsis. At RZ-1B and At RZ-1C were localized to nuclear speckles and interacted with a spectrum of serine/arginine-rich (SR) proteins through their C-termini. At RZ-1C preferentially bound to purine-rich RNA sequences in vitro through its N-terminal RNA recognition motif. Disrupting the RNA-binding activity of At RZ-1C with SR proteins through over-expression of the C-terminus of At RZ-1C conferred defective phenotypes similar to those observed in At rz-1b/At rz-1c double mutants, including delayed seed germination, reduced stature, and serrated leaves. Loss of function of At RZ-1B and At RZ-1C was accompanied by defective splicing of many genes and global perturbation of gene expression. In addition, we found that At RZ-1C directly targeted FLC, promoting efficient splicing of FLC introns and likely also repressing FLC transcription. Our findings highlight the critical role of At RZ-1B/1C in regulating RNA splicing, gene expression, and many key aspects of plant development via interaction with proteins including SR proteins. mRNA-seq to look at the transcriptome and splicing differences between wild type and At rz-1b At rz-1c mutant of Arabidopsis thaliana
Project description:Nuclear-localized RNA binding proteins are involved in various aspects of RNA metabolism, which in turn modulates gene expression. However, the functions of nuclear-localized RNA binding proteins in plants are poorly understood. Here we report the functions of two proteins containing RNA recognition motifs, At RZ-1B and At RZ-1C, in Arabidopsis. At RZ-1B and At RZ-1C were localized to nuclear speckles and interacted with a spectrum of serine/arginine-rich (SR) proteins through their C-termini. At RZ-1C preferentially bound to purine-rich RNA sequences in vitro through its N-terminal RNA recognition motif. Disrupting the RNA-binding activity of At RZ-1C with SR proteins through over-expression of the C-terminus of At RZ-1C conferred defective phenotypes similar to those observed in At rz-1b/At rz-1c double mutants, including delayed seed germination, reduced stature, and serrated leaves. Loss of function of At RZ-1B and At RZ-1C was accompanied by defective splicing of many genes and global perturbation of gene expression. In addition, we found that At RZ-1C directly targeted FLC, promoting efficient splicing of FLC introns and likely also repressing FLC transcription. Our findings highlight the critical role of At RZ-1B/1C in regulating RNA splicing, gene expression, and many key aspects of plant development via interaction with proteins including SR proteins.
Project description:Pre-mRNA splicing is important for gene expression in most eukaryotic organisms. Regulation occurs during pre-mRNA splicing greatly expanded the transcriptome complexity. Recent studies from Mammals, Drosophila and Yeast showed that the majority of introns are spliced co-transcriptionally. However, in plant the nature of co-transcriptionally splicing (CTS) and its regulation is still largely unknown. Here, through sequencing the chromatin-bound RNA (CB-RNA-seq), we studied the feature of CTS in Arabidopsis. We found CTS is widespread in Arabidopsis seedlings and a large proportion of alternative splicing events are determined co-transcriptionally. We found the CTS efficiency correlate with gene expression level, chromatin landscape and most surprisingly, the number of intron/exon of individual genes, whilst independent of gene length. In combination with iCLIP analysis, we found splicing regulator RZ-1B/1C promotes efficient CTS of thousands genes involving direct binding mainly to the exonic sequences. Interestingly, for many cases, the splicing promotion activity of RZ-1C does not associate with its binding to the regions immediately adjacent to the regulated intron. We propose a model of plant gene splicing, where multiple exon of individual gene is in favour of efficient CTS likely involving RZ-1C cooperative interactions with many exons and splicing factors. Our work uncovers the robustness of plant CTS and highlighted the role of RZ-1C in this process.
Project description:Serine/arginine-rich (SR) proteins are important splicing factors which play significant roles in spliceosome assembly and splicing regulation. However, little is known regarding their biological functions in plants. Here, we analyzed the phenotypes of mutants upon depleting different subfamilies of Arabidopsis SR proteins. We found that loss of the functions of SC35 and SC35-like (SCL) proteins cause pleiotropic changes in plant morphology and development, including serrated leaves, late flowering, shorter roots and abnormal silique phyllotaxy. Using RNA-seq, we found that SC35 and SCL proteins play roles in the pre-mRNA splicing. Motif analysis revealed that SC35 and SCL proteins preferentially bind to a specific RNA sequence containing the AGAAGA motif. In addition, the transcriptions of a subset of genes are affected by the deletion of SC35 and SCL proteins which interact with NRPB4, a specific subunit of RNA polymerase II. The splicing of FLOWERING LOCUS C (FLC) intron1 and transcription of FLC were significantly regulated by SC35 and SCL proteins to control Arabidopsis flowering. Therefore, our findings provide mechanistic insight into the functions of plant SC35 and SCL proteins in the regulation of splicing and transcription to maintain the proper expression of genes and development.
Project description:Alternative splicing (AS) of pre-mRNA is utilized by higher eukaryotes to achieve increased transcriptome and proteomic complexity. The serine/arginine (SR) splicing factors regulate tissue- or cell type-specific AS in a concentration and phosphorylation dependent manner. However, the mechanisms that modulate the cellular levels of active SR proteins remain to be elucidated. In the present study, we provide evidence for a role for the long nuclear-retained regulatory RNA (nrRNA), MALAT1 in AS regulation. MALAT1 interacts with SR proteins and influences the distribution of these and other splicing factors in nuclear speckle domains. Depletion of MALAT1 changes AS of endogenous pre-mRNAs, similar to what was observed upon overexpression of SR proteins. Furthermore, MALAT1 regulates cellular levels of phosphorylated forms of SR proteins. Taken together, our results suggest that MALAT1 regulates AS by modulating the levels of active SR proteins. Our results further highlight a novel role for a nrRNA in the regulation of gene expression. Malat1 Antisense and control knockdowns evaluated on a microarray platform to profile alternative splicing levels for 5782 cassette-type alternative exons.
Project description:Alternative splicing (AS) of pre-mRNA is utilized by higher eukaryotes to achieve increased transcriptome and proteomic complexity. The serine/arginine (SR) splicing factors regulate tissue- or cell type-specific AS in a concentration and phosphorylation dependent manner. However, the mechanisms that modulate the cellular levels of active SR proteins remain to be elucidated. In the present study, we provide evidence for a role for the long nuclear-retained regulatory RNA (nrRNA), MALAT1 in AS regulation. MALAT1 interacts with SR proteins and influences the distribution of these and other splicing factors in nuclear speckle domains. Depletion of MALAT1 changes AS of endogenous pre-mRNAs, similar to what was observed upon overexpression of SR proteins. Furthermore, MALAT1 regulates cellular levels of phosphorylated forms of SR proteins. Taken together, our results suggest that MALAT1 regulates AS by modulating the levels of active SR proteins. Our results further highlight a novel role for a nrRNA in the regulation of gene expression.
Project description:Eukaryotic cells have to prevent the export of unspliced pre-mRNAs until intron removal is completed to avoid the expression of aberrant and potentially harmful proteins. Only mature RNAs associate with the export receptor Mex67 (mammalian TAP) and enter the cytoplasm. The underlying nuclear quality control mechanisms are still unclear. Here we show that two shuttling SR-proteins Gbp2 and Hrb1 are key surveillance factors for the selective export of spliced mRNAs in yeast. Their absence leads to the significant leakage of unspliced pre-mRNAs into the cytoplasm. They bind to pre-mRNAs and the spliceosome during splicing, where they are necessary for the surveillance of splicing and the stable binding of the TRAMP-complex to the spliceosome-bound transcripts. Faulty transcripts are marked for their degradation at the nuclear exosome. On correct mRNAs the SR-proteins recruit Mex67 upon completion of splicing to allow a quality controlled nuclear export. Altogether, these data identify a role for shuttling SR-proteins in mRNA surveillance and nuclear mRNA quality control. 6 samples, i.e. 2 replicates per protein Gbp2, Hrb1 and Npl3
Project description:SR proteins are well-characterized RNA binding proteins that promote exon inclusion by binding to exonic splicing enhancers (ESEs). However, it has been unclear whether regulatory rules deduced on model genes apply generally to activities of SR proteins in the cell. Here, we report global analyses of two prototypical SR proteins SRSF1 (SF2/ASF) and SRSF2 (SC35) using splicing-sensitive arrays and CLIP-seq on mouse embryo fibroblasts (MEFs). Unexpectedly, we find that these SR proteins promote both inclusion and skipping of exons in vivo, but their binding patterns do not explain such opposite responses. Further analyses reveal that loss of one SR protein is accompanied by coordinated loss or compensatory gain in the interaction of other SR proteins at the affected exons. Therefore, specific effects on regulated splicing by one SR protein actually depend on a complex set of relationships with multiple other SR proteins in mammalian genomes. SRSF1 and SRSF2 CLIP-seq
Project description:Eukaryotic cells have to prevent the export of unspliced pre-mRNAs until intron removal is completed to avoid the expression of aberrant and potentially harmful proteins. Only mature RNAs associate with the export receptor Mex67 (mammalian TAP) and enter the cytoplasm. The underlying nuclear quality control mechanisms are still unclear. Here we show that two shuttling SR-proteins Gbp2 and Hrb1 are key surveillance factors for the selective export of spliced mRNAs in yeast. Their absence leads to the significant leakage of unspliced pre-mRNAs into the cytoplasm. They bind to pre-mRNAs and the spliceosome during splicing, where they are necessary for the surveillance of splicing and the stable binding of the TRAMP-complex to the spliceosome-bound transcripts. Faulty transcripts are marked for their degradation at the nuclear exosome. On correct mRNAs the SR-proteins recruit Mex67 upon completion of splicing to allow a quality controlled nuclear export. Altogether, these data identify a role for shuttling SR-proteins in mRNA surveillance and nuclear mRNA quality control.
Project description:Exon and expression analysis of HeLa cells after knockdown of SON Serine-arginine-rich (SR) proteins play a key role in alternative pre-mRNA splicing in eukaryotes. Our laboratory recently showed that a large SR protein called Son has unique repeat motifs that are essential for maintaining the subnuclear organization of pre-mRNA processing factors in nuclear speckles. Motif analysis of Son highlights putative RNA interaction domains that suggest a direct role for Son in pre-mRNA splicing. A genome-wide screen was performed to identify putative human transcription and splicing targets of Son.
Project description:Exon and expression analysis of HeLa cells after knockdown of SON Serine-arginine-rich (SR) proteins play a key role in alternative pre-mRNA splicing in eukaryotes. Our laboratory recently showed that a large SR protein called Son has unique repeat motifs that are essential for maintaining the subnuclear organization of pre-mRNA processing factors in nuclear speckles. Motif analysis of Son highlights putative RNA interaction domains that suggest a direct role for Son in pre-mRNA splicing. A genome-wide screen was performed to identify putative human transcription and splicing targets of Son. HeLa cells were transfected with siRNA against SON or a control siRNA (siLuciferase) for 48 hours. Five biological replicates were used for each condition.