Catalyzes the hydrolytic deamination of adenosine to inosine in double-stranded RNA (dsRNA) referred to as A-to-I RNA editing (PubMed:12426375). Acts primarily on non-coding regions of protein-coding genes including introns and untranslated regions (UTR) (PubMed:28925356, PubMed:25373143). Required for normal chemotaxis (PubMed:12426375, PubMed:14657490). Edits the 3' UTR of clec-41 which is required for normal clec-41 expression and for chemotaxis (PubMed:28925356). Plays a role in determining lifespan (PubMed:20011587, PubMed:25373143). Not required for RNA interference (PubMed:12419225). Likely to play a role in determining whether a dsRNA enters the RNAi pathway (PubMed:14657490). adenosine in double-stranded RNA + H(+) + H2O = inosine in double-stranded RNA + NH4(+) Interacts with A-to-I RNA editing regulator adr-1 (PubMed:24508457). Interacts with adbp-1; the interaction facilitates adr-2 nuclear localization (PubMed:18780728). Highest expression observed in the embryo. Levels decrease dramatically after embryogenesis, remain relatively constant during larval stages and increase again at the onset of adulthood. Can prevent somatic transgenes from inducing gene silencing via the RNA interference (RNAi) pathway. This may occur due to A-to-I editing of transgene-derived dsRNA, preventing transgene RNAi.