Processing bodies require RNA for assembly and contain nontranslating mRNAs.
Recent experiments have defined cytoplasmic foci, referred to as processing bodies (P-bodies), wherein mRNA decay factors are concentrated and where mRNA decay can occur. However, the physical nature of P-bodies, their relationship to translation, and possible roles of P-bodies in cellular responses remain unclear. We describe four properties of yeast P-bodies that indicate that P-bodies are dynamic structures that contain nontranslating mRNAs and function during cellular responses to stress. First, in vivo and in vitro analysis indicates that P-bodies are dependent on RNA for their formation. Second, the number and size of P-bodies vary in response to glucose deprivation, osmotic stress, exposure to ultraviolet light, and the stage of cell growth. Third, P-bodies vary with the status of the cellular translation machinery. Inhibition of translation initiation by mutations, or cellular stress, results in increased P-bodies. In contrast, inhibition of translation elongation, thereby trapping the mRNA in polysomes, leads to dissociation of P-bodies. Fourth, multiple translation factors and ribosomal proteins are lacking from P-bodies. These results suggest additional biological roles of P-bodies in addition to being sites of mRNA degradation.
Teixeira
Daniela
D
Department of Molecular and Cellular Biology & Howard Hughes Medical Institute, University of Arizona, Tucson, AZ 85721-0106, USA.
Sheth
Ujwal
U
Valencia-Sanchez
Marco A
MA
Brengues
Muriel
M
Parker
Roy
R
D003594:Cytoplasmic Granules / Q000235:genetics / Q000378:metabolism*; D053487:DEAD-box RNA Helicases; D004722:Endoribonucleases; D005838:Genotype; D005947:Glucose / Q000172:deficiency; D049452:Green Fluorescent Proteins; D018613:Microscopy, Confocal; D009997:Osmotic Pressure; D014176:Protein Biosynthesis; D020365:RNA Helicases / Q000378:metabolism; D020871:RNA Stability; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D015003:Yeasts / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins; C400572:DCP2 protein, S cerevisiae; D004722:Endoribonucleases; C445083:DHH1 protein, S cerevisiae; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases; D005947:Glucose