The role of N1-Src regulated splicing in neuronal differentiation

Alternative splicing (AS) is one of the main contributors to transcriptome diversity and functional complexity involved in the process of neuronal development. Evidence suggests that many splicing regulators and alternative splicing events are neuron-specific and aberrations in the regulation of these events have been linked to various neurodevelopmental disorders. N1-Src is an evolutionarily conserved neuronal splice variant of the ubiquitous tyrosine kinase c-Src. It has been implicated in neural development and as a prognostic indicator in neuroblastoma, a childhood cancer that is caused by failure of neural crest cells to differentiate. Results from knockdown experiments where N1 exon inclusion was prevented with splice-blocking antisense morpholino oligos revealed that N1-Src is a key regulator of primary neurogenesis in Xenopus. Preliminary short and long read RNA-Seq data from Xenopus embryos suggest a role for N1-Src in regulation of an alternative splicing programme during early neurogenesis, with transcripts encoding the splicing/RNA processing machinery themselves being the most spliced targets. This study aimed to further describe the N1-Src-regulated splicing network in the developing Xenopus nervous system using bioinformatic analysis of various publicly available and Evans/Isaacs lab RNASeq datasets. A differential splicing (DS) analysis pipeline was developed to detect and quantify alternative splicing events that occur during early stages of Xenopus embryo development relevant to neurogenesis. By correlating alternative splicing quantifications with RNA-binding protein motif enrichment analysis, this project proposed mechanisms for Src regulation of alternative splicing.