RBM-5 modulates U2AF large subunit-dependent alternative splicing in C. elegans
Ontology highlight
ABSTRACT: A key step in pre-mRNA splicing is the recognition of 3’ splicing sites by the U2AF large and small subunits, a process regulated by numerous trans-acting splicing factors. How these trans-acting factors interact with U2AF in vivo is unclear. From a screen for suppressors of the temperature-sensitive (ts) lethality of the C. elegans U2AF large subunit gene uaf-1(n4588) mutants, we identified mutations in the RNA binding motif gene rbm-5, a homolog of the tumor suppressor RBM5. rbm-5 mutations can suppress uaf-1(n4588) ts-lethality by loss of function and neuronal expression of rbm-5 was sufficient to rescue the suppression. Transcriptome analyses indicate that uaf-1(n4588) affected the expression of numerous genes and rbm-5 mutations can partially reverse the abnormal gene expression to levels similar to that of wild type. Though rbm-5 mutations did not obviously affect alternative splicing per se, they can suppress or enhance, in a gene-specific manner, the altered splicing of genes in uaf-1(n4588) mutants. Specifically, the recognition of a weak 3’ splice site was more susceptible to the effect of rbm-5. Our findings provide novel in vivo evidence that RBM-5 can modulate UAF-1-dependent RNA splicing and suggest that RBM5 might interact with U2AF large subunit to affect tumor formation.
Project description:RBM5, a regulator of alternative splicing of apoptotic genes, and its close homologues, RBM6 and RBM10, are RNA binding proteins frequently deleted or mutated in lung cancer. We report that RBM5/6 and RBM10 antagonistically regulate the proliferative capacity of cancer cells and display distinct positional effects in alternative splicing regulation. We identify the Notch pathway regulator NUMB as a key target of these factors in the control of cell proliferation. NUMB alternative splicing, which is frequently altered in lung cancer, can regulate colony and xenograft tumor formation and its modulation recapitulates or antagonizes the effects of RBM5, 6 and 10 in cell colony formation. RBM10 mutations identified in lung cancer cells disrupt NUMB splicing regulation to promote cell growth. Our results reveal a key genetic circuit in the control of cancer cell proliferation. CLIP-Seq analysis of RBM5, RBM6 and RBM10, with 2 biological replicates and one non-specific control for each protein.
Project description:RBM5, a regulator of alternative splicing of apoptotic genes, and its close homologues, RBM6 and RBM10, are RNA binding proteins frequently deleted or mutated in lung cancer. We report that RBM5/6 and RBM10 antagonistically regulate the proliferative capacity of cancer cells and display distinct positional effects in alternative splicing regulation. We identify the Notch pathway regulator NUMB as a key target of these factors in the control of cell proliferation. NUMB alternative splicing, which is frequently altered in lung cancer, can regulate colony and xenograft tumor formation and its modulation recapitulates or antagonizes the effects of RBM5, 6 and 10 in cell colony formation. RBM10 mutations identified in lung cancer cells disrupt NUMB splicing regulation to promote cell growth. Our results reveal a key genetic circuit in the control of cancer cell proliferation. RNA from 3 biological replicates of knockdowns of RBM5, 6 and 10 and a control set were used. Changes between the control and knockdowns were measured based on using a splice-junction array (Affymetrix HJAY).
Project description:The U2AF heterodimer has been well studied for its role in defining functional 3M-bM-^@M-^Y splice sites in pre-mRNA splicing, but many fundamental questions still remain unaddressed regarding the function of U2AF in mammalian genomes. Through genome-wide analysis of U2AF-RNA interactions, we report that U2AF has the capacity to directly define ~88% of functional 3M-bM-^@M-^Y splice sites in the human genome, but numerous U2AF binding events also occur in intronic locations. Mechanistic dissection reveals that upstream intronic binding events interfere with the immediate downstream 3M-bM-^@M-^Y splice site associated with either the alternative exon to cause exon skipping or with the competing constitutive exon to induce exon inclusion. We further demonstrate partial functional impairment with mutations in U2AF35, but not U2AF65, in regulated splicing. These findings reveal the genomic function and regulatory mechanism of U2AF in both normal and disease states. Examination of U2AF heterodimer regulated splicing in Hela cells with CLIP-seq (U2AF65), paired-end RNA-seq (si-NC and si-U2AF65) and RASL-seq (respective three biological replicates of WT, si-NC, si-U2AF65, si-U2AF35, si-NC + pcDNA3.0, si-U2AF65 + pcDNA3.0, and si-U2AF65 + Flag-U2AF35)
Project description:The U2AF heterodimer has been well studied for its role in defining functional 3’ splice sites in pre-mRNA splicing, but many fundamental questions still remain unaddressed regarding the function of U2AF in mammalian genomes. Through genome-wide analysis of U2AF-RNA interactions, we report that U2AF has the capacity to directly define ~88% of functional 3’ splice sites in the human genome, but numerous U2AF binding events also occur in intronic locations. Mechanistic dissection reveals that upstream intronic binding events interfere with the immediate downstream 3’ splice site associated with either the alternative exon to cause exon skipping or with the competing constitutive exon to induce exon inclusion. We further demonstrate partial functional impairment with mutations in U2AF35, but not U2AF65, in regulated splicing. These findings reveal the genomic function and regulatory mechanism of U2AF in both normal and disease states.
Project description:RBM5, a regulator of alternative splicing of apoptotic genes, and its close homologues, RBM6 and RBM10, are RNA binding proteins frequently deleted or mutated in lung cancer. We report that RBM5/6 and RBM10 antagonistically regulate the proliferative capacity of cancer cells and display distinct positional effects in alternative splicing regulation. We identify the Notch pathway regulator NUMB as a key target of these factors in the control of cell proliferation. NUMB alternative splicing, which is frequently altered in lung cancer, can regulate colony and xenograft tumor formation and its modulation recapitulates or antagonizes the effects of RBM5, 6 and 10 in cell colony formation. RBM10 mutations identified in lung cancer cells disrupt NUMB splicing regulation to promote cell growth. Our results reveal a key genetic circuit in the control of cancer cell proliferation.
Project description:RBM5, a regulator of alternative splicing of apoptotic genes, and its close homologues, RBM6 and RBM10, are RNA binding proteins frequently deleted or mutated in lung cancer. We report that RBM5/6 and RBM10 antagonistically regulate the proliferative capacity of cancer cells and display distinct positional effects in alternative splicing regulation. We identify the Notch pathway regulator NUMB as a key target of these factors in the control of cell proliferation. NUMB alternative splicing, which is frequently altered in lung cancer, can regulate colony and xenograft tumor formation and its modulation recapitulates or antagonizes the effects of RBM5, 6 and 10 in cell colony formation. RBM10 mutations identified in lung cancer cells disrupt NUMB splicing regulation to promote cell growth. Our results reveal a key genetic circuit in the control of cancer cell proliferation.
Project description:RNA-binding proteins (RBPs) are key players regulating RNA processing and are associated with disorders ranging from cancer to neurodegeneration. Here, we present a proteomics workflow for large-scale identification of RBPs and their RNA-binding regions in the mammalian brain identifying 526 RBPs including 86 previously undescribed. Analysing brain tissue from the Huntington’s disease (HD) R6/2 mouse model uncovered differential RNA-binding of the alternative splicing regulator RBM5. Combining several omics workflows, we show that RBM5 binds differentially to transcripts enriched in pathways of neurodegeneration in R6/2 brain tissue. We further find these transcripts to undergo changes in splicing and demonstrate that RBM5 directly regulates these changes in human neurons derived from embryonic stem cells. Finally, we reveal that RBM5 interacts differently with several known huntingtin interactors and components of huntingtin aggregates. Collectively, we demonstrate the applicability of our method for capturing RNA interactor dynamics in the contexts of tissue and disease.
Project description:RNA Binding Motif 5 (RBM5) is a nuclear splicing factor. Prior studies show that RBM5 overexpression in cancer cells alters gene splicing, gene expression, and induces cell death and/or growth arrest. The role of RBM5 in primary neurons is unknown, and its potential mRNA targets have not been identified. Using lentivirus based approaches we tested if RBM5 knockdown (i.e. by shRNA) or RBM5 overexpression (DDK-tagged rat open reading frame) alters whole genome expression in primary rat cortical neurons. We used microarrays to examine genes that are up-regulated vs. down-regulation in cortical neurons after RBM5 knockdown vs. overexpression.
Project description:RBM5 and RBM10 are RNA-binding proteins and splicing regulators. These two proteins are putative paralogs in mammalian cells, sharing common domain organization and extensive protein sequence similarity, but their RNA-binding preferences differ. We developed a sensitive system to identify splicing events regulated by RBM5 and/or RBM10, deleting all RBM5 alleles in 293Flp-In cells, and reducing the expression of RBM10, which is partially rescued by activation of a cryptic exon (CE) in one of the RBM10 alleles. RBM5 or RBM10 transgenes were then introduced in these RBM5-null, RBM10 mutant cells (RBM5-/-;RBM10-/CE), allowing controlled protein expression, induced with Doxycycline. Using this system we identify thousands of RBM5 and RBM10-regulated cassette exons, and note a substantial overlap between the two sets.