Eukaryotic mRNA decapping.
Eukaryotic mRNAs are primarily degraded by removal of the 3' poly(A) tail, followed either by cleavage of the 5' cap structure (decapping) and 5'->3' exonucleolytic digestion, or by 3' to 5' degradation. mRNA decapping represents a critical step in turnover because this permits the degradation of the mRNA and is a site of numerous control inputs. Recent analyses suggest decapping of an mRNA consists of four central and related events. These include removal, or inactivation, of the poly(A) tail as an inhibitor of decapping, exit from active translation, assembly of a decapping complex on the mRNA, and sequestration of the mRNA into discrete cytoplasmic foci where decapping can occur. Each of these steps is a demonstrated, or potential, site for the regulation of mRNA decay. We discuss the decapping process in the light of these central properties, which also suggest fundamental aspects of cytoplasmic mRNA physiology that connect decapping, translation, and storage of mRNA.
Coller
Jeff
J
Howard Hughes Medical Institute, Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721, USA. jmcoller@u.arizona.edu
Parker
Roy
R
D018389:Codon, Nonsense; D004722:Endoribonucleases / Q000378:metabolism; D005057:Eukaryotic Cells; D046911:Macromolecular Substances; D008954:Models, Biological; D015388:Organelles / Q000378:metabolism; D039102:Poly(A)-Binding Proteins / Q000378:metabolism; D012315:RNA Caps / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020871:RNA Stability; D012261:Ribonucleoproteins / Q000737:chemistry / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism
D018389:Codon, Nonsense; D046911:Macromolecular Substances; D039102:Poly(A)-Binding Proteins; D012315:RNA Caps; D012261:Ribonucleoproteins; C030052:mRNA decapping enzymes; C026452:messenger ribonucleoprotein; D004722:Endoribonucleases