Project description:Alternative splicing is a key process underlying the evolution of increased proteomic and functional complexity and is especially prevalent in the mammalian nervous system. However, the factors and mechanisms governing nervous system-specific alternative splicing are not well understood. Through a genome-wide computational and expression profiling strategy, we have identified a tissue- and vertebrate-restricted Ser/Arg (SR)-repeat splicing factor, the neural-specific SR-related protein of 100 kDa (nSR100). We show that nSR100 regulates an extensive network of brain-specific alternative exons enriched in genes that function in neural cell differentiation. nSR100 acts by increasing the levels of the neural/brain-enriched polypyrimidine tract binding protein and by interacting with its target transcripts. Disruption of nSR100 prevents neural cell differentiation in cell culture and in the developing zebrafish. Our results thus reveal a critical neural-specific alternative splicing regulator, the evolution of which has contributed to increased complexity in the vertebrate nervous system. A microarray platform to profile alternative splicing levels for 8714 cassette-type alternative exons across a diverse spectrum of mouse tissues.
Project description:Alternative splicing is a key process underlying the evolution of increased proteomic and functional complexity and is especially prevalent in the mammalian nervous system. However, the factors and mechanisms governing nervous system-specific alternative splicing are not well understood. Through a genome-wide computational and expression profiling strategy, we have identified a tissue- and vertebrate-restricted Ser/Arg (SR)-repeat splicing factor, the neural-specific SR-related protein of 100 kDa (nSR100). We show that nSR100 regulates an extensive network of brain-specific alternative exons enriched in genes that function in neural cell differentiation. nSR100 acts by increasing the levels of the neural/brain-enriched polypyrimidine tract binding protein and by interacting with its target transcripts. Disruption of nSR100 prevents neural cell differentiation in cell culture and in the developing zebrafish. Our results thus reveal a critical neural-specific alternative splicing regulator, the evolution of which has contributed to increased complexity in the vertebrate nervous system.
Project description:Alternative splicing (AS) generates vast transcriptomic complexity in the vertebrate nervous system. However, the extent to which trans-acting splicing regulators and their target AS regulatory networks contribute to nervous system development is not completely understood. To address these questions, we have generated mice lacking the vertebrate- and neural-specific Ser/Arg-repeat related protein of 100 kDa (nSR100/SRRM4). Loss of nSR100 impairs development of the central and peripheral nervous systems, in part by disrupting neurite outgrowth, cortical layering in the forebrain, and axon guidance in the corpus callosum. Accompanying these developmental defects are widespread changes in AS that primarily result in shifts to non-neural patterns for different classes of splicing events. The main component of the altered AS program comprises 3-27 nucleotide neural microexons, an emerging class of highly conserved alternative splicing event associated with the regulation of protein interaction networks in developing neurons and neurological disorders. Remarkably, inclusion of a 6-nucleotide nSR100-activated microexon in Unc13b transcripts is sufficient to rescue a neuritogenesis defect in nSR100 mutant primary neurons. These results thus reveal critical in vivo neurodevelopmental functions of nSR100, and they further link these functions to a conserved program of neural microexon splicing. mRNA profiles of mouse control or nSR100/Srrm4 KO cortex or hippocampus using high-throughput sequencing data.