title: Deadenylation is prerequisite for P-body formation and mRNA decay in mammalian cells.
abstract: Deadenylation is the major step triggering mammalian mRNA decay. One consequence of deadenylation is the formation of nontranslatable messenger RNA (mRNA) protein complexes (messenger ribonucleoproteins [mRNPs]). Nontranslatable mRNPs may accumulate in P-bodies, which contain factors involved in translation repression, decapping, and 5'-to-3' degradation. We demonstrate that deadenylation is required for mammalian P-body formation and mRNA decay. We identify Pan2, Pan3, and Caf1 deadenylases as new P-body components and show that Pan3 helps recruit Pan2, Ccr4, and Caf1 to P-bodies. Pan3 knockdown causes a reduction of P-bodies and has differential effects on mRNA decay. Knocking down Caf1 or overexpressing a Caf1 catalytically inactive mutant impairs deadenylation and mRNA decay. P-bodies are not detected when deadenylation is blocked and are restored when the blockage is released. When deadenylation is impaired, P-body formation is not restorable, even when mRNAs exit the translating pool. These results support a dynamic interplay among deadenylation, mRNP remodeling, and P-body formation in selective decay of mammalian mRNA.
authors.affiliation: Department of Biochemistry and Molecular Biology, The University of Texas Medical School, Houston, TX 77030, USA.
authors.forename: Dinghai
authors.initials: D
authors.lastname: Zheng
authors.forename: Nader
authors.initials: N
authors.lastname: Ezzeddine
authors.forename: Chyi-Ying A
authors.initials: CY
authors.lastname: Chen
authors.forename: Wenmiao
authors.initials: W
authors.lastname: Zhu
authors.forename: Xiangwei
authors.initials: X
authors.lastname: He
authors.forename: Ann-Bin
authors.initials: AB
authors.lastname: Shyu
mesh_terms: D000818:Animals; D022083:Cytoplasmic Structures / Q000187:drug effects / Q000378:metabolism*; D005095:Exoribonucleases; D006801:Humans; D051379:Mice; D008954:Models, Biological; D046912:Multiprotein Complexes / Q000378:metabolism; D041681:NIH 3T3 Cells; D011061:Poly A / Q000378:metabolism; D026723:Polyadenylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D011506:Proteins / Q000378:metabolism; D011691:Puromycin / Q000494:pharmacology; D020871:RNA Stability / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D054398:Receptors, CCR4 / Q000378:metabolism; D012097:Repressor Proteins; D012260:Ribonucleases
chemical_list: C515355:Ccr4 protein, mouse; D046912:Multiprotein Complexes; D011506:Proteins; D012333:RNA, Messenger; D054398:Receptors, CCR4; D012097:Repressor Proteins; D011061:Poly A; D011691:Puromycin; C489778:Cnot7 protein, mouse; D005095:Exoribonucleases; D012260:Ribonucleases