Functional link between the mammalian exosome and mRNA decapping.
Mechanistic understanding of mammalian mRNA turnover remains incomplete. We demonstrate that the 3' to 5' exoribonuclease decay pathway is a major contributor to mRNA decay both in cells and in cell extract. An exoribonuclease-dependent scavenger decapping activity was identified that follows decay of the mRNA and hydrolyzes the residual cap. The decapping activity is associated with a subset of the exosome proteins in vivo, implying a higher-order degradation complex consisting of exoribonucleases and a decapping activity, which together coordinate the decay of an mRNA. These findings indicate that following deadenylation of mammal mRNA, degradation proceeds by a coupled 3' to 5' exoribonucleolytic activity and subsequent hydrolysis of the cap structure by a scavenger decapping activity.
Wang
Z
Z
Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ 08854, USA.
Kiledjian
M
M
D000818:Animals; D002458:Cell Fractionation; D004722:Endoribonucleases; D005095:Exoribonucleases / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D020014:K562 Cells; D008322:Mammals; D009097:Multienzyme Complexes; D039381:RNA Cap-Binding Proteins; D012315:RNA Caps / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional / Q000502:physiology*; D020871:RNA Stability; D012331:RNA, Fungal / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism
D005656:Fungal Proteins; D009097:Multienzyme Complexes; D039381:RNA Cap-Binding Proteins; D012315:RNA Caps; D012331:RNA, Fungal; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; C100868:DCP1 protein, S cerevisiae; D004722:Endoribonucleases; D005095:Exoribonucleases