title: Edc3p and a glutamine/asparagine-rich domain of Lsm4p function in processing body assembly in Saccharomyces cerevisiae.
abstract: Processing bodies (P-bodies) are cytoplasmic RNA granules that contain translationally repressed messenger ribonucleoproteins (mRNPs) and messenger RNA (mRNA) decay factors. The physical interactions that form the individual mRNPs within P-bodies and how those mRNPs assemble into larger P-bodies are unresolved. We identify direct protein interactions that could contribute to the formation of an mRNP complex that consists of core P-body components. Additionally, we demonstrate that the formation of P-bodies that are visible by light microscopy occurs either through Edc3p, which acts as a scaffold and cross-bridging protein, or via the "prionlike" domain in Lsm4p. Analysis of cells defective in P-body formation indicates that the concentration of translationally repressed mRNPs and decay factors into microscopically visible P-bodies is not necessary for basal control of translation repression and mRNA decay. These results suggest a stepwise model for P-body assembly with the initial formation of a core mRNA-protein complex that then aggregates through multiple specific mechanisms.
authors.affiliation: Department of Molecular and Cellular Biology and Howard Hughes Medical Institute, University of Arizona, Tucson, AZ 85721.
authors.forename: Carolyn J
authors.initials: CJ
authors.lastname: Decker
authors.forename: Daniela
authors.initials: D
authors.lastname: Teixeira
authors.forename: Roy
authors.initials: R
authors.lastname: Parker
mesh_terms: D001216:Asparagine / Q000737:chemistry*; D003593:Cytoplasm / Q000378:metabolism; D005973:Glutamine / Q000737:chemistry*; D008954:Models, Biological; D009841:Oligonucleotides / Q000737:chemistry; D014176:Protein Biosynthesis; D017434:Protein Structure, Tertiary; D020871:RNA Stability; D017414:Ribonucleoprotein, U4-U6 Small Nuclear / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000378:metabolism / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: C488957:EDC3 protein, S cerevisiae; C093543:LSM4 protein, S cerevisiae; D009841:Oligonucleotides; D017414:Ribonucleoprotein, U4-U6 Small Nuclear; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; C026452:messenger ribonucleoprotein; D005973:Glutamine; D001216:Asparagine