CircAI: a comprehensive database of CircRNA associated with A-to-I RNA editing

RNA editing is a prevalent posttranscriptional modification characterized by single-base alterations in RNA transcripts, leading to diverse functional consequences, such as codon changes, mRNA splicing modulation, and regulation of noncoding RNAs, including their binding sites. Although next-generation sequencing has identified over 2 million adenosine-to-inosine (A-to-I) RNA editing sites in mammalian transcriptomes, the functional significance of the majority of these sites, especially those in noncoding regions, remains poorly understood. To address this gap and provide a comprehensive resource for exploring the functional impact of RNA editing in circular RNAs (circRNAs), we conducted an in-depth analysis of A-to-I editing sites in circRNAs across eight species (Homo sapiens, Mus musculus, Macaca mulatta, Gallus gallus, Rattus norvegicus, Oryctolagus cuniculus, Sus scrofa, and Danio rerio). All gathered data have been integrated into CircAI (circRNA associated with A-to-I RNA editing), the first database to combine multispecies circRNA editing data with functional predictions. CircAI offers a user-friendly platform for exploring the functional impact of RNA editing on circRNAs, including predictions of coding potential, miRNA interactions, secondary structures, and RNA editing quantitative trait loci (edQTL). By providing detailed annotations and dynamic visualization tools, CircAI serves as a pivotal resource for advancing research on the functional roles of RNA editing in circRNAs and their implications in disease.