The unique mechanism suggested by Daniel et al. [1] is reminiscent of an aircraft carrier which serves as a convenient landing field for planes. In this case, EIEs on the RNA molecule provide a highly efficient binding site, which recruits multiple ADARs to a location in proximity to the specific target. Thus, the study indicates a new important role for long dsRNAs and dsRNA binding domains (dsRBDs) of ADAR in increasing the local concentration of enzyme in the vicinity of the site targeted for editing. This results in highly efficient editing at the selected site.
Since the long dsRNA is also promiscuously edited by ADAR enzymes, a reasonable speculation may be that these elements also have a role in releasing the ADARs from the RNA molecule. In this way, a molecule that has attracted a very high concentration of enzyme will be eventually hyperedited at the long stem, lowering the ability to recruit further ADARs (Fig. 1b).
Long dsRNAs are largely composed of reversely oriented non-coding retrotransposons, which constitute approximately half of the mammalian genome. The effect of these elements in the cell is mostly unclear and they are generally considered non-functional. Daniel et al. provide a new noteworthy regulatory meaning for some of these mobile elements by showing they induce RNA editing activity. This may be also valid for additional dsRNA-binding proteins, potentially extending the role of these elements.