Drosophila melanogaster
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA102305 | ENA |
REPOSITORIES: ENA
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Project description:In animals, egg activation triggers a cascade of posttranscriptional events that act on maternally synthesized RNAs. We show that, in Drosophila, the PAN GU (PNG) kinase sits near the top of this cascade, triggering translation of SMAUG (SMG), a multifunctional posttranscriptional regulator conserved from yeast to humans. Although PNG is required for cytoplasmic polyadenylation of smg mRNA, it regulates translation via mechanisms that are independent of its effects on the poly(A) tail. Analyses of mutants suggest that PNG relieves translational repression by PUMILIO (PUM) and one or more additional factors, which act in parallel through the smg mRNA's 3' untranslated region (UTR). Microarray-based gene expression profiling shows that SMG is a major regulator of maternal transcript destabilization. SMG-dependent mRNAs are enriched for gene ontology annotations for function in the cell cycle, suggesting a possible causal relationship between failure to eliminate these transcripts and the cell cycle defects in smg mutants. Keywords: Identification of Maternal mRNAs
2007-09-14 | GSE8910 | GEO
Project description:The maternal mRNA nanos is required for anterior-posterior patterning in the early Drosophila melanogaster development. The nanos-mRNA is translationally repressed and deadenylated during the first two hours of embryogenesis. A stem-loop structure in the 3'-UTR of this RNA (SRE - Smaug recogniiton element) is bound by the Smaug protein which recruits a protein complex to the RNA to sequester its translation and intiate transcript degradation via the ccr4/not-complex. To analyse the composition of this repressor complex, biotinylated RNAs carrying two SRE stem-loops were used for an affinity purification of bound proteins. As a negative control an RNA was used that contained two point mutations in the SRE loop, that abolish binding of Smaug. Seven subunits were identified as components of the repressor complex. The main deadenylase in Drosophila, the ccr4/not-complex was also significantly enriched.
2017-07-18 | PXD006596 | Pride
Project description:Background: Metazoan embryos undergo a maternal-to-zygotic transition (MZT) during which a subset of maternal gene products is eliminated and the zygotic genome becomes transcriptionally active. RNA-binding proteins (RBPs) and the microRNA-induced silencing complex (miRISC) – of which Argonaute 1 (AGO1) is a key component in Drosophila – target maternal mRNAs for degradation. The Drosophila Smaug, Brain tumor (BRAT) and Pumilio (PUM) RBPs direct the degradation of maternal mRNAs. Here we elucidate Smaug’s roles in regulation of miRNAs and miRISC during the MZT. Results: By global analysis of small RNAs at several stages during the MZT, we show that the vast majority of all miRNA species encoded by the Drosophila genome (85%) are expressed during the MZT. Whereas a subset of these miRNAs is loaded into oocytes by the mother and stays at constant levels during the MZT, dozens of miRNA species are either newly synthesized or re-expressed in the early embryo. Loss of Smaug has a profound effect on miRNAs but little effect on piRNAs or siRNAs. Smaug is required for production of new miRNAs during the MZT; Smaug-bound AGO1 reflects the constellation and abundance of the miRNAs present in early embryos; and Smaug is required for the increase in AGO1 protein levels that occurs during the MZT. As a consequence of low miRISC activity in smaug mutants, maternal mRNAs that are normally targeted for degradation by zygotic miRNAs fail to be cleared. BRAT and PUM share target mRNAs with miRISC during the MZT while the miR-309 miRNA family coregulates targets of BRAT but not PUM. Conclusions: Smaug controls the MZT through direct targeting of a subset of maternal mRNAs for degradation and, indirectly, through production and function of miRNAs and miRISC, which control clearance of a distinct subset of maternal mRNAs. BRAT and/or PUM function together with miRISC during the latter process. With respect to miRISC-dependent transcript degradation, Smaug is required (1) for the synthesis of miRNAs, (2) for synthesis and stabilization of AGO1, and (3) for action of AGO1 in association with its bound miRNAs. In smaug mutants a large number of maternal mRNAs persist and the MZT fails.
2016-09-06 | GSE82194 | GEO
Project description:During the maternal-to-zygotic transition (MZT), which encompasses the earliest stages of animal embryogenesis, a subset of maternally supplied gene products is cleared, thus permitting activation of zygotic gene expression. In the Drosophila melanogaster embryo, the RNA-binding protein Smaug plays an essential role in progression through the MZT by regulating the translational repression and degradation of a large number of maternal mRNA species. The Smaug protein itself is rapidly cleared at the end of the MZT by the Skp/Cullin/F-box (SCF) E3-ligase complex; clearance of Smaug requires zygotic transcription. Here, we show that an F-box protein, which we name Bard (encoded by CG14317), is required for degradation of Smaug. Bard is expressed zygotically and physically interacts with Smaug at the end of the MZT, coincident with binding of the maternal SCF proteins, SkpA and Cullin1, and with degradation of Smaug. We show that shRNA-mediated knock-down of Bard or deletion of the bard gene in the early embryo results in stabilization of Smaug protein, a phenotype that is rescued by transgenes expressing Bard .
2021-10-06 | MSV000088199 | MassIVE
Project description:The Smaug RNA-binding protein is essential for microRNA synthesis during the Drosophila maternal-to-zygotic transition
| PRJNA324276 | ENA
Project description:Pumilio (PUM) is a Drosophila member of a conserved family of sequence-specific RNA-binding proteins that have been shown to regulate mRNA stability and/or translation in a variety of organisms. PUM has been shown to repress the translation of several mRNAs in the Drosophila early embryo; failure to repress these targets leads to lethal developmental defects. Here we use a combination of microarray-based gene expression profiling and next-generation sequencing to identify more than 200 mRNAs that are associated with full-length PUM protein in early embryos and to define a global role for PUM in mRNA decay. Surprisingly, despite the fact that PUM is maternally supplied and thus is present from the beginning of embryogenesis, the vast majority of PUM-directed decay occurs only after zygotic genome activation. We show that the smaug mRNA, which itself encodes an RNA-binding protein that directs transcript decay, is a direct target of PUM via binding sites in the smg 3'UTR. Whereas the endogenous smaug mRNA and the transgenic reporter mRNA that carries the smaug 3'UTR undergo decay after zygotic genome activation, a reporter with an array of PUM-binding sites decays before zygotic genome activation. These data support a model in which additional cis-elements in the smg 3'UTR delay decay until after zygotic genome activation.
2017-07-01 | GSE48645 | GEO
Project description:Background: Metazoan embryos undergo a maternal-to-zygotic transition (MZT) during which a subset of maternal gene products is eliminated and the zygotic genome becomes transcriptionally active. RNA-binding proteins (RBPs) and the microRNA-induced silencing complex (miRISC) â of which Argonaute 1 (AGO1) is a key component in Drosophila â target maternal mRNAs for degradation. The Drosophila Smaug, Brain tumor (BRAT) and Pumilio (PUM) RBPs direct the degradation of maternal mRNAs. Here we elucidate Smaugâs roles in regulation of miRNAs and miRISC during the MZT. Results: By global analysis of small RNAs at several stages during the MZT, we show that the vast majority of all miRNA species encoded by the Drosophila genome (85%) are expressed during the MZT. Whereas a subset of these miRNAs is loaded into oocytes by the mother and stays at constant levels during the MZT, dozens of miRNA species are either newly synthesized or re-expressed in the early embryo. Loss of Smaug has a profound effect on miRNAs but little effect on piRNAs or siRNAs. Smaug is required for production of new miRNAs during the MZT; Smaug-bound AGO1 reflects the constellation and abundance of the miRNAs present in early embryos; and Smaug is required for the increase in AGO1 protein levels that occurs during the MZT. As a consequence of low miRISC activity in smaug mutants, maternal mRNAs that are normally targeted for degradation by zygotic miRNAs fail to be cleared. BRAT and PUM share target mRNAs with miRISC during the MZT while the miR-309 miRNA family coregulates targets of BRAT but not PUM. Conclusions: Smaug controls the MZT through direct targeting of a subset of maternal mRNAs for degradation and, indirectly, through production and function of miRNAs and miRISC, which control clearance of a distinct subset of maternal mRNAs. BRAT and/or PUM function together with miRISC during the latter process. With respect to miRISC-dependent transcript degradation, Smaug is required (1) for the synthesis of miRNAs, (2) for synthesis and stabilization of AGO1, and (3) for action of AGO1 in association with its bound miRNAs. In smaug mutants a large number of maternal mRNAs persist and the MZT fails. Examination of miRNA expresssion at different time points in wild type and smuag mutant early embryos .
2016-09-06 | E-GEOD-82194 | biostudies-arrayexpress
Project description:miR-309-dependent unstable maternal mRNAs are stabilized in smaug mutants
| PRJNA109611 | ENA
Project description:SMAUG is required for zygotic transcription during the maternal-zygotic transition MZT
| PRJNA109609 | ENA
Project description:Cytoplasmic polyadenylation is a major regulator of mRNA fate during oogenesis and egg activation.
| PRJNA321817 | ENA