title: Scavenger decapping activity facilitates 5' to 3' mRNA decay.
abstract: mRNA degradation occurs through distinct pathways, one primarily from the 5' end of the mRNA and the second from the 3' end. Decay from the 3' end generates the m7GpppN cap dinucleotide, which is subsequently hydrolyzed to m7Gp and ppN in Saccharomyces cerevisiae by a scavenger decapping activity termed Dcs1p. Although Dcs1p functions in the last step of mRNA turnover, we demonstrate that its activity modulates earlier steps of mRNA decay. Disruption of the DCS1 gene manifests a threefold increase of the TIF51A mRNA half-life. Interestingly, the hydrolytic activity of Dcs1p was essential for the altered mRNA turnover, as Dcs1p, but not a catalytically inactive Dcs1p mutant, complemented the increased mRNA stability. Mechanistic analysis revealed that 5' to 3' exoribonucleolytic activity was impeded in the dcs1Delta strain, resulting in the accumulation of uncapped mRNA. These data define a new role for the Dcs1p scavenger decapping enzyme and demonstrate a novel mechanism whereby the final step in the 3' mRNA decay pathway can influence 5' to 3' exoribonucleolytic activity.
authors.affiliation: Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, USA.
authors.forename: Hudan
authors.initials: H
authors.lastname: Liu
authors.forename: Megerditch
authors.initials: M
authors.lastname: Kiledjian
mesh_terms: D015152:Blotting, Northern; D015153:Blotting, Western; D002384:Catalysis; D018076:DNA, Complementary / Q000378:metabolism; D005838:Genotype; D006868:Hydrolysis; D047468:Immunoprecipitation; D008715:Methionine / Q000737:chemistry; D008954:Models, Biological; D009699:N-Glycosyl Hydrolases / Q000378:metabolism / Q000502:physiology*; D010448:Peptide Initiation Factors / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D011061:Poly A / Q000737:chemistry; D014176:Protein Biosynthesis; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism / Q000502:physiology*; D013997:Time Factors; D000097574:Eukaryotic Translation Initiation Factor 5A
chemical_list: D018076:DNA, Complementary; D008715:Methionine; D009699:N-Glycosyl Hydrolases; D010448:Peptide Initiation Factors; D011061:Poly A; D012313:RNA; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D000097574:Eukaryotic Translation Initiation Factor 5A; C478395:DCS1 protein, S cerevisiae