Targeting an mRNA for decapping: displacement of translation factors and association of the Lsm1p-7p complex on deadenylated yeast mRNAs.
The major pathway of eukaryotic mRNA decay involves deadenylation-dependent decapping followed by 5' to 3' exonucleolytic degradation. By examining interactions among mRNA decay factors, the mRNA, and key translation factors, we have identified a critical transition in mRNP organization that leads to decapping and degradation of yeast mRNAs. This transition occurs after deadenylation and includes loss of Pab1p, eIF4E, and eIF4G from the mRNA and association of the decapping activator complex, Lsm1p-7p, which enhances the coimmunoprecipitation of a decapping enzyme complex (Dcp1p and Dcp2p) with the mRNA. These results define an important rearrangement in mRNP organization and suggest that deadenylation promotes mRNA decapping by both the loss of Pab1p and the recruitment of the Lsm1p-7p complex.
Tharun
S
S
Department of Molecular and Cellular Biology, Howard Hughes Medical Institute, University of Arizona, 1007 E. Lowell, Tucson, AZ 85721, USA. tharun@u.arizona.edu
Parker
R
R
D004268:DNA-Binding Proteins / Q000378:metabolism; D004722:Endoribonucleases; D039561:Eukaryotic Initiation Factor-4E; D039603:Eukaryotic Initiation Factor-4G; D005656:Fungal Proteins / Q000378:metabolism*; D010448:Peptide Initiation Factors / Q000378:metabolism; D039102:Poly(A)-Binding Proteins; D011233:Precipitin Tests; D039381:RNA Cap-Binding Proteins; D012315:RNA Caps / Q000378:metabolism*; D012331:RNA, Fungal / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism; D012261:Ribonucleoproteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins
D004268:DNA-Binding Proteins; D039561:Eukaryotic Initiation Factor-4E; D039603:Eukaryotic Initiation Factor-4G; D005656:Fungal Proteins; C114069:LSM1 protein, S cerevisiae; C103266:PAT1 protein, S cerevisiae; D010448:Peptide Initiation Factors; D039102:Poly(A)-Binding Proteins; D039381:RNA Cap-Binding Proteins; D012315:RNA Caps; D012331:RNA, Fungal; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; C026452:messenger ribonucleoprotein; C100868:DCP1 protein, S cerevisiae; C400572:DCP2 protein, S cerevisiae; D004722:Endoribonucleases