GW body disassembly triggered by siRNAs independently of their silencing activity.
GW bodies (or P-bodies) are cytoplasmic granules containing proteins involved in both mRNA degradation and storage, including the RNA interference machinery. Their mechanism of assembly and function are still poorly known although their number depends upon the flux of mRNA to be stored or degraded. We show here that silencing of the translational regulator CPEB1 leads to their disappearance, as reported for other GW body components. Surprisingly, the same results were obtained with several siRNAs targeting genes encoding proteins unrelated to mRNA metabolism. The disappearance of GW bodies did not correlate with the silencing activity of the siRNA and did not inhibit further silencing by siRNA. Importantly, in most cases, GW bodies were rapidly reinduced by arsenite, indicating that their assembly was not prevented by the inhibition of the targeted or off-target genes. We therefore propose that some siRNA sequences affect mRNA metabolism so as to diminish the amount of mRNA directed to the GW bodies. As an exception, GW bodies were not reinduced following Rck/p54 depletion by interference, indicating that this component is truly required for the GW body assembly. Noteworthy, Rck/p54 was dispensable for the assembly of stress granules, in spite of their close relationship with the GW bodies.
Serman
A
A
CNRS FRE2937, Institut André Lwoff, 7 rue Guy Moquet, 94801 Villejuif cedex, France.
Le Roy
F
F
Aigueperse
C
C
Kress
M
M
Dautry
F
F
Weil
D
D
D018053:Arsenites / Q000494:pharmacology; D002460:Cell Line; D003594:Cytoplasmic Granules / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D053487:DEAD-box RNA Helicases / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007372:Interferons / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism*; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics; D039221:mRNA Cleavage and Polyadenylation Factors / Q000037:antagonists & inhibitors / Q000235:genetics
D018053:Arsenites; C490386:CPEB1 protein, human; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D014157:Transcription Factors; D039221:mRNA Cleavage and Polyadenylation Factors; D007372:Interferons; C094683:DDX6 protein, human; D053487:DEAD-box RNA Helicases; C015001:arsenite