Benefits of Careful Editing
Science · 2000
In eukaryotes, the faithful copying of DNA sequences into RNA transcripts does not in itself ensure that an organism can produce the diverse array of proteins it needs. The initial RNA transcripts, called precursor messenger RNAs (pre-mRNAs), experience a series of tightly regulated processing events, such as the splicing reactions that remove nocoding sequences, or introns. An additional, less common form of pre-mRNA processing is called RNA editing. In one type of editing, adenosine (A) is converted to inosine (I) by an enzyme called ADAR (for adenosine deaminase acting on RNA). In the case of the pre-mRNAs encoding glutamate receptor subunits, this editing is site-specific and results in a mixture of functionally distinct proteins that differ by only one amino acid.