Publisher Summary The biological process of A-to-I RNA editing mediated by ADAR is discussed with new directions on potentially novel targets, including the widely expressed Alu retrotransposable elements found in noncoding regions of mRNA. Many events take place after the de novo synthesis of an RNA transcript, leading to alterations from its gene-encoded origin. In addition to posttranslational modification, which occurs after the production of the polypeptide chain, RNA can be modified in several ways as to vary the amino acid sequence before it is even translated. Once transcription has commenced, the newly formed pre-mRNA must be processed by several mechanisms that operate posttranscriptionally. The RNA itself plays a role in this regulatory process by forming an assortment of secondary structures. These complex elements in part are formed by the RNA sequence itself producing double-stranded (ds) RNA, creating a configuration of bulges, stem loops, and hairpins.