tRNA introns: Presence, processing, and purpose

The presence of introns in both protein-coding and noncoding RNA transcripts is a fascinating phenomenon. It seems counterintuitive that an organism would devote precious time and energy to removing a nucleic acid sequence that will not be present in the final product. Nevertheless, introns (including self-splicing ones) are clearly important components of the basic cellular process of gene expression. Transfer RNA (tRNA) introns have been detected in all three kingdoms of life, and their precise removal is crucial for tRNA function. Of particular interest to this review are the tRNA intronic circular RNAs (tricRNAs) that form during metazoan tRNA splicing. In animal cells, these ultrastable introns form a novel class of noncoding RNA. Here, we summarize established knowledge and describe new findings in the field of tRNA splicing. This article is categorized under: RNA Processing > Splicing Mechanisms RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems RNA in Disease and Development > RNA in Disease RNA Processing > tRNA Processing.