82
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Edc3p and a glutamine/asparagine-rich domain of Lsm4p function in processing body assembly in Saccharomyces cerevisiae

      research-article
      , ,
      The Journal of Cell Biology
      The Rockefeller University Press

      Read this article at

      ScienceOpenPublisherPMC
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          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.

          Related collections

          Most cited references41

          • Record: found
          • Abstract: found
          • Article: not found

          Genomic libraries and a host strain designed for highly efficient two-hybrid selection in yeast.

          The two-hybrid system is a powerful technique for detecting protein-protein interactions that utilizes the well-developed molecular genetics of the yeast Saccharomyces cerevisiae. However, the full potential of this technique has not been realized due to limitations imposed by the components available for use in the system. These limitations include unwieldy plasmid vectors, incomplete or poorly designed two-hybrid libraries, and host strains that result in the selection of large numbers of false positives. We have used a novel multienzyme approach to generate a set of highly representative genomic libraries from S. cerevisiae. In addition, a unique host strain was created that contains three easily assayed reporter genes, each under the control of a different inducible promoter. This host strain is extremely sensitive to weak interactions and eliminates nearly all false positives using simple plate assays. Improved vectors were also constructed that simplify the construction of the gene fusions necessary for the two-hybrid system. Our analysis indicates that the libraries and host strain provide significant improvements in both the number of interacting clones identified and the efficiency of two-hybrid selections.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Relief of microRNA-mediated translational repression in human cells subjected to stress.

            In metazoans, most microRNAs imperfectly base-pair with the 3' untranslated region (3'UTR) of target mRNAs and prevent protein accumulation by either repressing translation or inducing mRNA degradation. Examples of specific mRNAs undergoing microRNA-mediated repression are numerous, but whether the repression is a reversible process remains largely unknown. Here we show that cationic amino acid transporter 1 (CAT-1) mRNA and reporters bearing its 3'UTR can be relieved from the microRNA miR-122-induced inhibition in human hepatocarcinoma cells subjected to different stress conditions. The derepression of CAT-1 mRNA is accompanied by its release from cytoplasmic processing bodies and its recruitment to polysomes. The derepression requires binding of HuR, an AU-rich-element binding protein, to the 3'UTR of CAT-1 mRNA. We propose that proteins interacting with the 3'UTR will generally act as modifiers altering the potential of miRNAs to repress gene expression.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              P bodies and the control of mRNA translation and degradation.

              Recent results indicate that many untranslating mRNAs in somatic eukaryotic cells assemble into related mRNPs that accumulate in specific cytoplasmic foci referred to as P bodies. Transcripts associated with P body components can either be degraded or return to translation. Moreover, P bodies are also biochemically and functionally related to some maternal and neuronal mRNA granules. This suggests an emerging model of cytoplasmic mRNA function in which the rates of translation and degradation of mRNAs are influenced by a dynamic equilibrium between polysomes and the mRNPs seen in P bodies. Moreover, some mRNA-specific regulatory factors, including miRNAs and RISC, appear to repress translation and promote decay by recruiting P body components to individual mRNAs.
                Bookmark

                Author and article information

                Journal
                J Cell Biol
                jcb
                The Journal of Cell Biology
                The Rockefeller University Press
                0021-9525
                1540-8140
                5 November 2007
                : 179
                : 3
                : 437-449
                Affiliations
                Department of Molecular and Cellular Biology and Howard Hughes Medical Institute, University of Arizona, Tucson, AZ 85721
                Author notes

                Correspondence to R. Parker: rrparker@ 123456u.arizona.edu

                Article
                200704147
                10.1083/jcb.200704147
                2064791
                17984320
                a792218d-cea5-459e-bfb0-1aee6d73b9b7
                Copyright © 2007, The Rockefeller University Press
                History
                : 25 April 2007
                : 3 October 2007
                Categories
                Research Articles
                Article

                Cell biology
                Cell biology

                Comments

                Comment on this article