Mechanism Of RNA Recoding: New Twists In Brain Protein Production

From the March 17 issue of Nature:Rna

University of Connecticut Health Center scientist, Robert Reenan, has uncovered new rules of RNA recoding–a genetic editing method cells use to expand the number of proteins assembled from a single DNA code. According to his work, the shape a particular RNA adopts solely determines how editing enzymes modify the information molecule inside cells. The study may help explain the remarkable adaptability and evolution of animal nervous systems–including the human brain.

In the Figure: DNA (left) encodes the instructions for making protein, but cells can’t read them directly. Instead, the DNA code is copied first into RNA in a process called transcription. RNA includes coding regions that direct protein assembly (green) and non-coding regions–called introns–that play a regulatory role (yellow, pink). By studying the RNA code for the nervous- system protein, synaptotagmin, in several different insects, Reenan uncovered the general rules of RNA editing. Each insect’s RNA folds differently and the structures determine how the molecules get edited inside cells. This figure illustrates editing of fruit fly and butterfly RNA molecules. RNA folding brings regulatory regions (yellow, pink shapes) together with editing sites (green shapes). The resulting “knots” of fruit fly RNA (upper panel) and “loops” of butterfly RNA (lower panel) guides editing enzymes to sites destined for modification. RNA editing lets cells produce a variety of different proteins from a single DNA code (right). The altered proteins often have different functions from their unmodified counterparts. (Credit: Nicolle Rager, National Science Foundation)

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