Temporal and spatial control of germ-plasm RNAs.
In many species, germ cells form in a specialized germ plasm, which contains localized maternal RNAs. In the absence of active transcription in early germ cells, these maternal RNAs encode germ-cell components with critical functions in germ-cell specification, migration, and development. For several RNAs, localization has been correlated with release from translational repression, suggesting an important regulatory function linked to localization. To address the role of RNA localization and translational control more systematically, we assembled a comprehensive set of RNAs that are localized to polar granules, the characteristic germ-plasm organelles. We find that the 3'-untranslated regions (UTRs) of all RNAs tested control RNA localization and instruct distinct temporal patterns of translation of the localized RNAs. We demonstrate necessity for translational timing by swapping the 3'UTR of polar granule component (pgc), which controls translation in germ cells, with that of nanos, which is translated earlier. Translational activation of pgc is concurrent with extension of its poly(A) tail length but appears largely independent of the Drosophila CPEB homolog ORB. Our results demonstrate a role for 3'UTR mediated translational regulation in fine-tuning the temporal expression of localized RNA, and this may provide a paradigm for other RNAs that are found enriched at distinct cellular locations such as the leading edge of fibroblasts or the neuronal synapse.
Rangan
Prashanth
P
HHMI and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA.
DeGennaro
Matthew
M
Jaime-Bustamante
Kean
K
Coux
Rémi-Xavier
RX
Martinho
Rui G
RG
Lehmann
Ruth
R
D020413:3' Untranslated Regions / Q000502:physiology*; D000818:Animals; D004330:Drosophila / Q000235:genetics / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D005854:Germ Cells / Q000737:chemistry*; D026723:Polyadenylation; D042925:Positive Transcriptional Elongation Factor B / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis / Q000502:physiology*; D012313:RNA / Q000502:physiology*; D016601:RNA-Binding Proteins / Q000235:genetics
D020413:3' Untranslated Regions; D029721:Drosophila Proteins; D016601:RNA-Binding Proteins; C527201:pgc protein, Drosophila; C070574:nos protein, Drosophila; D012313:RNA; D042925:Positive Transcriptional Elongation Factor B