Large-scale RNA editing profiling in different adult chicken tissues

RNA editing is a post-transcription maturation process that diversifies genomically encoded information and can lead to diversity and complexity of transcriptome, especially in the brain. Thanks to next-generation sequencing technologies, a large number of editing sites have been identified in different species, especially in human, mouse and rat. While this mechanism is well described in mammals, only a few studies have been performed in the chicken. Here, we developed a rigorous computational strategy to identify RNA editing sites in eight different tissues of the chicken (brain, spleen, colon, lung, kidney, heart, testes and liver), based on RNA sequencing data alone. We identified 68 A-to-G editing sites in 46 genes. Only two of these were previously reported in chicken. We found no C-to-U sites, attesting the lack of this type of editing mechanism in the chicken. Similar to mammals, the editing sites were enriched in non-coding regions, rarely resulted in change of amino acids, showed a critical role in nervous system and had a low guanosine level upstream of the editing site and some enrichment downstream from the site. Moreover, in contrast to mammals, editing sites were weakly enriched in interspersed repeats and the frequency and editing ratio of non-synonymous sites were higher than those of synonymous sites.\n\nInterestingly, we found several tissue-specific edited genes including GABRA3, SORL1 and HTR1D in brain and RYR2 and FHOD3 in heart that were associated with functional processes relevant to the corresponding tissue. This finding highlighted the importance of the RNA editing in several chicken tissues, especially the brain. This study extends our understanding of RNA editing in chicken tissues and establish a foundation for further exploration of this process.