Recent advances of studies on alternative intron retention

Alternative splicing, allowing multiple mRNAs to be generated from a single gene, is a major source of proteome diversity in eukaryotes. Intron retention (IR), one type of alternative splicing, is the complete retention of an intron in a mature transcript. IR is believed to be associated with failure of the recognition of weak splice sites flanking introns. Mutations in DNA sequences, including point mutations and sequence insertions or deletions, can be at the origin and evolution of IR. The strength of weaker splice sites is the main cause of IR, but some cis-regulatory elements and trans-regulatory factors can also play crucial roles in regulating IR. IR can result in the regulation of gene expression and may contribute to increase protein diversity. IR has been shown to occur in a variety of diseases, and it frequently leads to aberrant splicing.