Recent advances in mammalian RNA editing.

RNA editing is a posttranscriptional modification that results in the generation of nucleotides within an RNA transcript that do not match the bases present within the genome. Mammalian RNA editing events, often represented by cytidine-to-uridine and adenosine-to-inosine conversions, are predominantly mediated by base deamination. In the past decade, important advances have been made in the understanding of editing mechanisms, the identification of RNA sequences and structures necessary for editing regulation, and the cloning and characterization of editing enzymes. It has also recently been appreciated that RNA editing within mammalian substrates can have profound functional consequences in protein function, implicating this posttranscriptional modification as important in the production of molecular diversity.