Genome Wide Co-transcriptional RNA editing in Drosophila
The regulation of gene expression includes a diverse set of post-transcriptional mechanisms such as RNA degradation, splicing, localization, and even RNA retention. Additionally, genomic mutations can have positive as well as negative consequences on protein function. RNA editing is an additional post-transcriptional modality, which occurs when the enzyme ADAR binds to a double-stranded RNA, deaminates a target adenosine, creating an inosine. This edited base is then interpreted as a guanosine in the ribosome, potentially changing the amino acid and adding to the translated protein repertoire. Whereas ADAR has been shown to localize to chromatin, no genomic study has described widespread co-transcriptional editing. To investigate this issue in the Drosophila head, we extracted nascent RNA from 12 samples and deep sequenced them using an Illumina GA2 sequencer. We found over 1300 edited sites, both in exons and introns, more than previously identified by any study. Our data also indicate that editing occurs on mRNAs with shorter inferred half-lives.