Accelerated evolution in the human lineage led to gain and loss of transcriptional enhancers in the RBFOX1 locus [midbrain]
Ontology highlight
ABSTRACT: A long-standing goal of evolutionary biology is to decode how changes in gene regulatory networks contribute to human-specific traits. Human Accelerated Regions (HARs) are prime candidates for driving gene regulatory modifications in human development. The RBFOX1 locus is densely populated with HARs, providing a set of potential regulatory elements that could have changed its expression in the human lineage. Here we examined the role of RBFOX1-HARs using transgenic zebrafish reporter assays and identified fifteen transcriptional enhancers that are active in the developing nervous system, ten of which displayed differential expression between the human and chimpanzee sequences. The engineered loss of two selected RBFOX1-HARs in knockout mouse models increased Rbfox1 expression at specific developmental stages and tissues in the brain, influencing the expression and splicing of a high number of Rbfox1 target genes. Our results provided insight into the spatial and temporal changes in gene expression driven by RBFOX1-HARs.
Project description:A long-standing goal of evolutionary biology is to decode how changes in gene regulatory networks contribute to human-specific traits. Human Accelerated Regions (HARs) are prime candidates for driving gene regulatory modifications in human development. The RBFOX1 locus is densely populated with HARs, providing a set of potential regulatory elements that could have changed its expression in the human lineage. Here we examined the role of RBFOX1-HARs using transgenic zebrafish reporter assays and identified fifteen transcriptional enhancers that are active in the developing nervous system, ten of which displayed differential expression between the human and chimpanzee sequences. The engineered loss of two selected RBFOX1-HARs in knockout mouse models increased Rbfox1 expression at specific developmental stages and tissues in the brain, influencing the expression and splicing of a high number of Rbfox1 target genes. Our results provided insight into the spatial and temporal changes in gene expression driven by RBFOX1-HARs.
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:The goal of this study was to investigate the regulatory events underlying post-transcriptional changes in gene expression, and more specifically in mRNA stability, in cancer. We observed that the stability of RBFOX1 targets was decreased in glioblastoma and, given that RBFOX1 is known to stabilize its targets mRNAs, we hypothesized that RBFOX1 down-regulation is responsible at least in part for alterations in the glioblastoma transcriptome. We overexpressed RBFOX1 in the A172 human glioblastoma cell line and performed RNA-sequencing on extracted RNA. We computed differential gene expression in the cell line overexpressing RBFOX1, compared to the control samples. We confirmed that RBFOX1 overexpression leads to an upregulation of the RBFOX1 regulon, including the majority of RBFOX1 targets that are destabilized in tumors. The results suggest that RBFOX1 downregulation in glioblastoma leads to the destabilization of its targets, which can be partially rescused through overexpression of RBFOX1.
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 microarray experiments. We performed microarray analysis to profile gene expression and splicing changes in mouse hippocampal cultures (14 DIV) with Rbfox1 and Rbfox3 double knockdown by siRNAs. Before the treatment of siRNAs, the hippocampal cultures were treated with AraC to eliminate glial cells and co-cultured with cortical cultures to support the growth of neurons. Six samples were analyzed.
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 iCLIP-seq experiments. We performed iCLIP procedures to identify Rbfox1 binding in the cytoplasm. Cultured mouse forebrain neurons were irradiated with UV and a cytoplasmic fraction was purified for immunoprecipitation. An anti-Rbfox1 antibody was used to immunoprecipitate Rbfox1 target RNAs and an anti-Flag antibody was used as control. Two samples were analyzed.
Project description:Dysregulation of the brain-enriched RNA binding protein Rbfox1 has been linked to neurologic diseases such as epilepsy and autism spectrum disorders. However, it remains unexplored how distinct neuronal populations might contribute to neurologic dysfunction resulting from Rbfox1 loss. To examine these issues we profiled gene expression specifically in the hippocampus of wildtype and Rbfox1-/- mice. We identified transcripts whose expression was strongly Rbfox1-dependent and exhibited significant Rbfox1 binding in their 3’UTRs. One prominent target, Vamp1, was found to be specifically expressed in GABAergic interneurons. Both Vamp1 knockdown and Rbfox1 loss led to decreased synaptic transmission, and altered E/I balance in the Rbfox1-/- hippocampus, indicating that Vamp1 loss is a major component of the Rbfox1-/- physiological phenotype. The cytoplasmic isoform of Rbfox1 was sufficient to rescue Vamp1 expression in Rbfox1-/- neurons. We show that Rbfox1 binding in the Vamp1 3’UTR promotes its expression in part by antagonizing the brain-enriched microRNA-9. These results demonstrate that inhibitory neurons maintain specialized synaptic vesicle release machinery containing Vamp1 that is critically regulated by Rbfox1.
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.
Project description:We used RNA sequencing to identify the RBFOX1 splicing network at a genome-wide level in primary human neural stem cells during differentiation. We observe that RBFOX1 regulates a large set of alternative splicing events implicated in neurogenesis and cell maintenance. Subsequent alterations in gene expression define an additional transcriptional network regulated by RBFOX1 involved in neurodevelopmental pathways remarkably parallel to those affected by splicing. RNA sequencing at a 75bp single-end read scale was performed using polyA-enriched RNA from 5 biological replicates of primary human neural progenitor cell lines generated by lentiviral-mediated knockdown of GFP (control) or RBFOX1 and differentiated for 4 weeks.
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 microarray experiments.
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 iCLIP-seq experiments.