Open AccessP-Body Formation Is a Consequence, Not the Cause, of RNA-Mediated Gene Silencing
Author(s) -
Ana Eulálio,
Isabelle BehmAnsmant,
Daniel Schweizer,
Elisa Izaurralde
Publication year - 2007
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.00128-07
Subject(s) - gene silencing , biology , p bodies , rna induced silencing complex , polysome , argonaute , rna silencing , trans acting sirna , microbiology and biotechnology , rna interference , rna induced transcriptional silencing , messenger rna , rna , small interfering rna , nonsense mediated decay , gene , genetics , translation (biology) , rna splicing , ribosome
P bodies are cytoplasmic domains that contain proteins involved in diverse posttranscriptional processes, such as mRNA degradation, nonsense-mediated mRNA decay (NMD), translational repression, and RNA-mediated gene silencing. The localization of these proteins and their targets in P bodies raises the question of whether their spatial concentration in discrete cytoplasmic domains is required for posttranscriptional gene regulation. We show that processes such as mRNA decay, NMD, and RNA-mediated gene silencing are functional in cells lacking detectable microscopic P bodies. Although P bodies are not required for silencing, blocking small interfering RNA or microRNA silencing pathways at any step prevents P-body formation, indicating that P bodies arise as a consequence of silencing. Consistently, we show that releasing mRNAs from polysomes is insufficient to trigger P-body assembly: polysome-free mRNAs must enter silencing and/or decapping pathways to nucleate P bodies. Thus, even though P-body components play crucial roles in mRNA silencing and decay, aggregation into P bodies is not required for function but is instead a consequence of their activity.