title: GW-Bodies and P-Bodies Constitute Two Separate Pools of Sequestered Non-Translating RNAs.
abstract: Non-translating RNAs that have undergone active translational repression are culled from the cytoplasm into P-bodies for decapping-dependent decay or for sequestration. Organisms that use microRNA-mediated RNA silencing have an additional pathway to remove RNAs from active translation. Consequently, proteins that govern microRNA-mediated silencing, such as GW182/Gw and AGO1, are often associated with the P-bodies of higher eukaryotic organisms. Due to the presence of Gw, these structures have been referred to as GW-bodies. However, several reports have indicated that GW-bodies have different dynamics to P-bodies. Here, we use live imaging to examine GW-body and P-body dynamics in the early Drosophila melanogaster embryo. While P-bodies are present throughout early embryonic development, cytoplasmic GW-bodies only form in significant numbers at the midblastula transition. Unlike P-bodies, which are predominantly cytoplasmic, GW-bodies are present in both nuclei and the cytoplasm. RNA decapping factors such as DCP1, Me31B, and Hpat are not associated with GW-bodies, indicating that P-bodies and GW-bodies are distinct structures. Furthermore, known Gw interactors such as AGO1 and the CCR4-NOT deadenylation complex, which have been shown to be important for Gw function, are also not present in GW-bodies. Use of translational inhibitors puromycin and cycloheximide, which respectively increase or decrease cellular pools of non-translating RNAs, alter GW-body size, underscoring that GW-bodies are composed of non-translating RNAs. Taken together, these data indicate that active translational silencing most likely does not occur in GW-bodies. Instead GW-bodies most likely function as repositories for translationally silenced RNAs. Finally, inhibition of zygotic gene transcription is unable to block the formation of either P-bodies or GW-bodies in the early embryo, suggesting that these structures are composed of maternal RNAs.
authors.affiliation: Department of Biological Sciences and Eleanor Roosevelt Institute, University of Denver, Denver, Colorado, United States of America.
authors.forename: Prajal H
authors.initials: PH
authors.lastname: Patel
authors.affiliation: Department of Biological Sciences and Eleanor Roosevelt Institute, University of Denver, Denver, Colorado, United States of America.|Molecular and Cellular Biophysics Program, University of Denver, Denver, Colorado, United States of America.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Barbee
authors.affiliation: Department of Biological Sciences and Eleanor Roosevelt Institute, University of Denver, Denver, Colorado, United States of America.|Molecular and Cellular Biophysics Program, University of Denver, Denver, Colorado, United States of America.
authors.forename: J Todd
authors.initials: JT
authors.lastname: Blankenship
mesh_terms: D000818:Animals; D060565:Argonaute Proteins / Q000235:genetics; D003593:Cytoplasm / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics; D004331:Drosophila melanogaster / Q000235:genetics; D035683:MicroRNAs / Q000235:genetics; D014176:Protein Biosynthesis / Q000235:genetics*; D034622:RNA Interference / Q000502:physiology; D062085:RNA, Long Noncoding / Q000235:genetics*; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: C489654:AGO1 protein, Drosophila; D060565:Argonaute Proteins; D029721:Drosophila Proteins; C513405:Gw protein, Drosophila; D035683:MicroRNAs; D062085:RNA, Long Noncoding