Project description:The Rbfox family of splicing factors regulate alternative splicing during animal development and in disease, impacting thousands of exons in the maturing brain, heart, and muscle. Rbfox proteins have long been known to bind to the RNA sequence GCAUG with high affinity, but just half of Rbfox CLIP peaks contain a GCAUG motif. We incubated recombinant RBFOX2 with over 60,000 mouse and human transcriptomic sequences to reveal significant binding to several moderate-affinity, non-GCAYG sites at a physiologically relevant range of RBFOX concentrations. We find that many of these “secondary motifs” bind Rbfox robustly in cells and that several together can exert regulation comparable to a GCAUG in a trichromatic splicing reporter assay. Furthermore, secondary motifs regulate RNA splicing in neuronal development and in neuronal subtypes where cellular Rbfox concentrations are highest, enabling a second wave of splicing changes as Rbfox levels increase.
Project description:Alternative splicing has critical roles in diverse cellular, developmental and pathological processes. However, the full repertoires of factors that control individual splicing events are not known. We describe a CRISPR-based screening strategy for the systematic identification of genes that control 3-27 nt microexons with functions in nervous system development and that are commonly disrupted in autism. Besides known regulators including nSR100/Srrm4, Rbfox and Ptbp1, approximately 200 additional genes impact microexon splicing. These genes are enriched in genetic links to autism. Two of the screen hits, Srsf11 and Rnps1, preferentially regulate Srrm4-dependent microexons relative to other exons. These factors form mutually stabilizing interactions with Srrm4 that bridge upstream intronic enhancer elements and exonic sequences to activate microexon splicing. Our study thus presents a system for the genome-wide definition of splicing regulatory networks and further reveals a mechanism for the recognition of microexons with critical roles in nervous system development and disorders.
Project description:Alternative splicing has critical roles in diverse cellular, developmental and pathological processes. However, the full repertoires of factors that control individual splicing events are not known. We describe a CRISPR-based screening strategy for the systematic identification of genes that control 3-27 nt microexons with functions in nervous system development and that are commonly disrupted in autism. Besides known regulators including nSR100/Srrm4, Rbfox and Ptbp1, approximately 200 additional genes impact microexon splicing. These genes are enriched in genetic links to autism. Two of the screen hits, Srsf11 and Rnps1, preferentially regulate Srrm4-dependent microexons relative to other exons. These factors form mutually stabilizing interactions with Srrm4 that bridge upstream intronic enhancer elements and exonic sequences to activate microexon splicing. Our study thus presents a system for the genome-wide definition of splicing regulatory networks and further reveals a mechanism for the recognition of microexons with critical roles in nervous system development and disorders.
Project description:Alternative splicing has critical roles in diverse cellular, developmental and pathological processes. However, the full repertoires of factors that control individual splicing events are not known. We describe a CRISPR-based screening strategy for the systematic identification of genes that control 3-27 nt microexons with functions in nervous system development and that are commonly disrupted in autism. Besides known regulators including nSR100/Srrm4, Rbfox and Ptbp1, approximately 200 additional genes impact microexon splicing. These genes are enriched in genetic links to autism. Two of the screen hits, Srsf11 and Rnps1, preferentially regulate Srrm4-dependent microexons relative to other exons. These factors form mutually stabilizing interactions with Srrm4 that bridge upstream intronic enhancer elements and exonic sequences to activate microexon splicing. Our study thus presents a system for the genome-wide definition of splicing regulatory networks and further reveals a mechanism for the recognition of microexons with critical roles in nervous system development and disorders.
Project description:Alternative splicing has critical roles in diverse cellular, developmental and pathological processes. However, the full repertoires of factors that control individual splicing events are not known. We describe a CRISPR-based screening strategy for the systematic identification of genes that control 3-27 nt microexons with functions in nervous system development and that are commonly disrupted in autism. Besides known regulators including nSR100/Srrm4, Rbfox and Ptbp1, approximately 200 additional genes impact microexon splicing. These genes are enriched in genetic links to autism. Two of the screen hits, Srsf11 and Rnps1, preferentially regulate Srrm4-dependent microexons relative to other exons. These factors form mutually stabilizing interactions with Srrm4 that bridge upstream intronic enhancer elements and exonic sequences to activate microexon splicing. Our study thus presents a system for the genome-wide definition of splicing regulatory networks and further reveals a mechanism for the recognition of microexons with critical roles in nervous system development and disorders.
Project description:Human genetic studies have identified the neuronal RNA binding protein, Rbfox1, as a candidate gene for autism spectrum disorders. While Rbfox1 functions as a splicing regulator in the nucleus, it is also alternatively spliced to produce cytoplasmic isoforms. To investigate cytoplasmic Rbfox1, we knocked down Rbfox proteins in mouse neurons and rescued with cytoplasmic or nuclear Rbfox1. Transcriptome profiling showed that nuclear Rbfox1 rescued splicing changes induced by knockdown, whereas cytoplasmic Rbfox1 rescued changes in mRNA levels. iCLIP-seq of subcellular fractions revealed that in nascent RNA Rbfox1 bound predominantly to introns, while cytoplasmic Rbox1 bound to 3' UTRs. Cytoplasmic Rbfox1 binding increased target mRNA stability and translation, and overlapped significantly with miRNA binding sites. Cytoplasmic Rbfox1 target mRNAs were enriched in genes involved in cortical development and autism. Our results uncover a new Rbfox1 regulatory network and highlight the importance of cytoplasmic RNA metabolism to cortical development and disease. In this data set, we included the data from RNA-seq experiments. We performed RNA-seq to profile gene expression and splicing changes. The expression levels of Rbfox1 and Rbfox3 in cultured mouse hippocampal neurons were reduced by siRNAs. The reduction of Rbfox1 and 3 was rescued by expression of cytoplasmic or nuclear Rbfox1 splice isoform. The gene expression and splicing profiles were compared between different treatments. Eight samples were analyzed.
Project description:To assess the requirement of Nova2 for alternative processing of RNA in mouse brain. Protein-RNA interactions play critical roles in all aspects of gene expression. Here we develop a genome-wide means of mapping protein-RNA binding sites in vivo, by high throughput sequencing of RNA isolated by crosslinking immunoprecipitation (HITS-CLIP). HITS-CLIP analysis of the neuron-specific splicing factor Nova2 revealed extremely reproducible RNA binding maps in multiple mouse brains. These maps provide genome-wide in vivo biochemical footprints confirming the previous prediction that the position of Nova binding determines the outcome of alternative splicing; moreover, they are sufficiently powerful to predict Nova action de novo. HITS-CLIP revealed a large number of Nova-RNA interactions in 3â UTRs, leading to the discovery that Nova regulates alternative polyadenylation in the brain. HITS-CLIP, therefore, provides a robust, unbiased means to identify functional protein-RNA interactions in vivo. Keywords: Comparative analysis Refer to individual Series. This SuperSeries is composed of the following subset Series: GSE17374: Wild type vs. Nova2 KO mouse: Exon array data GSE17376: Wild type vs. Nova2 KO mouse: Exon junction array data
Project description:Rett syndrome (RTT) is a severe neurological disorder which is mainly caused by mutations found in the X-linked gene encoding MeCP2. Despite extensive studies, the molecular functions of MeCP2 remain elusive. Here, we report that MeCP2 is a new subunit of a higher-order multiunit protein complex Rbfox/LASR and acts as a scaffold for this splicing complex. Deletion or mutation of MeCP2 leads to defects in forming MeCP2/Rbfox/LASR complex and aberrant alternative pre-mRNA splicing. Our data link RTT to an impaired function of MeCP2 in splicing control through its role in nucleating Rbfox/LASR macromolecule assembly.
Project description:We have identified Mbnl2 mediated splicing events and mRNA expression regulation by comparing WT and Mbnl2 ΔE2/ΔE2 mouse hippocampii using Affymetrix Mouse Exon Junction Array and mRNA sequencing. The splicing microarray data has already been submitted under GSE37908 which also includes a re-analysis of RNA-seq data. The TableS1.xls contains Splicing microarray analysis data of Mbnl2+/+ vs. MBNL2 ΔE2/ΔE2 knockout hippocampus. The TableS2.xls files contain RNA-Seq, Gene Ontology, HITS-CLIP and CIMS summary of Mbnl2+/+ vs. MBNL2 ΔE2/ΔE2 knockout hippocampus. The file contents are descibed in the 'TableS1_S2_readme.pdf' and data processing details are included in the 'data_processing_readme.pdf' file. The Mbnl2_TableS2.xls contains data from exon junction microarrays for splicing analysis between WT and Mbnl2 delta2 mice. It also contains RNA-seq based splicing analysis between WT and Mbnl2 delta2 mice. Mbnl2_TableS2 further contains common targets between the two analyses, Gene Ontology and finally the HITS-CLIP data. CLIP tag summary describes read numbers for the three biological replicates. CLIP sig peaks contains significant HITS-CLIP unique reads/peaks after processing the data (BED files). Finally, CIMS analysis describes the Mbnl2 binding motif.