Effects of A-to-I RNA editing on noncoding transcripts. (a) primary microRNA (pri-miRNAs) are subject to editing by ADARs, which may block the drosha cleavage step and subject the transcript to degradation by Tudor-SN (tudor staphylococcal nuclease), as in the case of miR142.35 (b) If drosha cutting is unaffected by editing, or if the pre-miRNA itself is edited, processing by dicer may be blocked as in the case of miR151.36 (c) If mature edited miRNAs are produced, (d) the targets of the miRNA can be changed, as in the case of miR376a-5p.37 (e) Alterations in miRNA stability could hypothetically affect active-strand selection.8 (f) Long dsRNAs, such as viral RNAs, are very efficiently and nonspecifically edited by ADARs, resulting in inhibition of RNAi,33 and degradation by Tudor-SN.38,39 (g) ADAR1p150 can tightly bind small interfering RNAs (siRNAs) without editing them, reducing their concentration and thereby decreasing the effectiveness of RNA interference (RNAi).