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The Eukaryotic mRNA Cycle: Movement of yeast mRNAs between polysomes and P‐bodies and its role in translational regulation.
Author(s) -
Parker Roy Robert,
Brengues Muriel,
Coller Jeff,
Sheth Ujwal,
Sanchez Marco,
Teixeira Daniela
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a456
Subject(s) - polysome , translation (biology) , p bodies , messenger rna , microbiology and biotechnology , translational regulation , untranslated region , biology , eukaryotic translation , eif4e , protein biosynthesis , five prime untranslated region , psychological repression , gene expression , gene , rna , genetics , ribosome
Translational control is an important aspect of the regulation of gene expression in eukaryotic cells. In addition to the translating pool of mRNA associated with polysomes, recent experiments have defined cytoplasmic foci, referred to as P bodies, wherein untranslated mRNAs accumulate and where mRNA decapping and decay can occur. We now present several lines of evidence that yeast mRNAs within P‐bodies can also return to translation. For example, reporter mRNAs exit translation and concentrate in P‐bodies when translation initiation is blocked, and resume translation and exit P‐bodies when translation is restored. These results define a cycle of mRNA movement wherein mRNAs travel from polysomes to P‐bodies and then back to the translating pool. This mRNA cycle has several important properties and identifies three critical decision points in controlling the function of mRNAs: 1) the mechanism of targeting transcripts to P‐bodies, 2) deciding the fate of transcripts within P‐bodies, and 3) the mechanism by which transcripts return to translation. Additional experiments show that accumulation of mRNAs in P‐bodies is required for global translation repression. This suggests that translation repression by sequestration into P‐bodies is competitively balanced with translation and shifts in this balance play a role in translational control.