Recent advances of studies on alternative intron retention

Abstract

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.

Expression of the glycolytic enzymes enolase and lactate dehydrogenase during the early phase of Toxoplasma differentiation is regulated by an intron retention mechanism

“…ENO2 intron‐retention was never observed in RT‐PCR experiments using PLK brain cysts, in vitro tachyzoites or peritoneal tachyzoites as source of RNA. IR is part of a wider process called alternative splicing, one of the main mechanisms responsible for increasing the diversity and complexity of genomes (Zhan, ). Splicing events such as exon skipping, truncation, extension, cryptic exons, and IR have been observed in many genes of several organisms, particularly in higher multicellular organisms.…”

“…Several reports show that expression of key cellular factors may also be regulated by posttranscription mechanisms such as time-regulated splicing (Averbeck et al, 2005;Xu et al, 2008;Yap et al, 2012;Boothby et al, 2013;Zhan, 2013). Among these processes, intron retention (IR) is a type of alternative splicing exploited by cells to provide messengers that cannot be translated until a stimulus triggers splicing of the regulated intron(s), licensing these messengers to produce their coded product (Boothby et al, 2013).…”

A novel mutation from gene splicing of a voltage-gated sodium channel in a marine copepod and its potential effect on channel function

“…It appears that under other circumstances, which are unknown, both spliceosomes work in conjunction, splicing in part of the intron, which corresponds to the insertion and substitution, to produce the mutant isoform. Incorporation of introns into functional products has been characterized in general (Zhan, 2013), and voltage-gated ion channels in particular (e.g., Drosophila) (Wu and Krainer, 1999). Testing of this hypothesis was beyond the scope of this study, but merits attention.…”