Harnessing Human ADAR2 for Site-Directed RNA Editing

Abstract

The catalytic deamination of adenosine to inosine is an essential posttranscriptional RNA modification. Since Inosine is biochemically read as guanosine, site-specific A-to-I RNA editing results in substitution of single amino acids and can lead to changes in processing and regulation of transcripts. Because of the high potential for manipulating protein function and RNA processing, we are developing tools to re-direct RNA editing in a site-specific way by applying engineered SNAP-tagged deaminases. However, this strategy, as well as strategies by others, requires the presence of an engineered deaminase in the target tissue. With respect to this limitation we have now designed short guideRNAs that harness the endogenously expressed deaminase for site-directed RNA editing. We demonstrate the new method to edit user-defined targets with high specificity and yield. Editing was successfully optimized in vitro and in cell culture depending on a fully genetically encodable basis. This editing system has a high potential towards investigating and manipulating RNA processing and protein functions within current topics of biomedical issues.