Genome-wide identification of intrasplicing events in the human transcriptome and hints to their regulatory potential

Alternative splicing is one of the major regulators of transcriptome diversity and individual isoform abundance. Identifying and understanding the scope and variety of splicing events is still an ongoing process. We established a novel pipeline to extract splicing events from specific RNA-sequencing datasets and identified numerous splicing events that did not span the entirety of the respective annotated intron. These events occurred in introns of all lengths. After confirmation of these splice events by conventional methodologies, we analyzed the impact of intrasplicing on full intron removal. This showed that these intronic splicing steps can be beneficial, deleterious or neutral for full intron removal. This in part confirms recent findings on recursive splicing events in humans and other vertebrates and further uncovers an additional level of transcriptome regulation based on a yet undiscovered level of flexibility and regulation of splice site selection and its impact on gene expression.