Synthetic construct
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PROVIDER: PRJNA258416 | ENA |
REPOSITORIES: ENA
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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: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:BRAT-associated mRNAs and PUM-associated mRNAs were identified in early Drosophila embryos by RNA co-immunoprecipitation of the endogenous proteins using synthetic antibodies, followed by microarray analysis (RIP-Chip). Nine RNA co-immunoprecipitations were performed. This includes 3 biological replicates each of 1) anti-BRAT RNA co-immunoprecipitations from wild-type 0-3 hour embryos, 2) anti-PUM RNA co-immunoprecipitations from wild-type 0-3 hour embryos, and 3) control antibody RNA co-immunoprecipitations from wild-type 0-3 hour embryos. BRAT samples and PUM samples were each normalized separately with the control samples, for a total of 12 processed samples (3 BRAT with 3 control normalized together, and 3 PUM with 3 control normalized together) from the 9 RNA co-immunoprecipitations.
2015-03-28 | E-GEOD-60466 | biostudies-arrayexpress
Project description:BRAT-associated mRNAs and PUM-associated mRNAs were identified in early Drosophila embryos by RNA co-immunoprecipitation of the endogenous proteins using synthetic antibodies, followed by microarray analysis (RIP-Chip).
2015-03-28 | GSE60466 | GEO
Project description:Maternal mRNAs are synthesized during oogenesis to initiate the development of future generations. Some maternal mRNAs are determinants of somatic or germline fate and must be translationally repressed until embryogenesis. However, the translational repressors themselves are also temporally regulated. We use polar granule component (pgc), a Drosophila maternal mRNA, as a model system to ask how maternal mRNAs are repressed while the regulatory landscape is continually shifting. pgc, a potent transcriptional silencer and germline determinant, is translationally regulated throughout oogenesis. We find that the 3’UTR of pgc mRNA contains a conserved ten-nucleotide sequence that is bound by different conserved RNA binding proteins (RBPs) at different stages of oogenesis to continuously repress translation except for a brief expression in the stem cell daughter. Pumilio (Pum) binds to this sequence in undifferentiated and early differentiating oocytes and recruits other temporally restricted translational regulators to block pgc translation. After differentiation, Pum levels diminish and Bruno (Bru) levels increase, allowing Bru to bind the same 3’UTR sequence and take over translational repression of pgc mRNA. We have identified a class of maternal mRNAs regulated during oogenesis by both Pum and Bru, including Zelda, activator of the zygotic genome, which contain this core 10-nt regulatory sequence. Our data suggests that this hand off mechanism is more generally utilized to inhibit translation of maternal mRNAs during oogenesis.
2018-09-05 | GSE119457 | GEO
Project description:Maternal mRNAs are synthesized during oogenesis to initiate the development of future generations. Some maternal mRNAs are determinants of somatic or germline fate and must be translationally repressed until embryogenesis. However, the translational repressors themselves are also temporally regulated. We use polar granule component (pgc), a Drosophila maternal mRNA, as a model system to ask how maternal mRNAs are repressed while the regulatory landscape is continually shifting. pgc, a potent transcriptional silencer and germline determinant, is translationally regulated throughout oogenesis. We find that the 3’UTR of pgc mRNA contains a conserved ten-nucleotide sequence that is bound by different conserved RNA binding proteins (RBPs) at different stages of oogenesis to continuously repress translation except for a brief expression in the stem cell daughter. Pumilio (Pum) binds to this sequence in undifferentiated and early differentiating oocytes and recruits other temporally restricted translational regulators to block pgc translation. After differentiation, Pum levels diminish and Bruno (Bru) levels increase, allowing Bru to bind the same 3’UTR sequence and take over translational repression of pgc mRNA. We have identified a class of maternal mRNAs regulated during oogenesis by both Pum and Bru, including Zelda, activator of the zygotic genome, which contain this core 10-nt regulatory sequence. Our data suggests that this hand off mechanism is more generally utilized to inhibit translation of maternal mRNAs during oogenesis.
2018-09-05 | GSE119456 | GEO
Project description:During the first stages of development, the fertilized germ cells rapidly transition to totipotency. Maternally deposited mRNAs encode the proteins necessary for reprogramming the transcriptionally quiescent zygotic genome during this maternal-to-zygotic transition (MZT). The transcription factor Zelda is essential for this reprogramming in the Drosophila embryo. Zelda is necessary for transcriptional activation of the zygotic genome, and the absence of Zelda leads to embryonic lethality during the MZT. Excess Zelda activity is also lethal to the embryo, demonstrating that Zelda levels must be precisely controlled during early development. Because Zelda is encoded by a maternally deposited mRNA, Zelda levels in the embryo are controlled at the level of translation. To understand how levels of this essential reprogramming factor were regulated to allow for embryonic development and zygotic genome activation, we investigated the factors that regulated translation of zelda. Brain Tumor (BRAT) is a translational regulator that was previously shown to bind to zelda mRNA in the embryo. We showed that BRAT functions to repress zelda translation, as embryos deficient for maternal BRAT activity prematurely express Zelda. We further showed that in the larval brain, BRAT similarly regulates Zelda levels and identified specific BRAT-binding sites that mediate these effects. Thus, BRAT regulates Zelda in multiple tissues. Because both too little and too much Zelda are lethal to the embryo, we hypothesized that precocious expression of this transcriptional activator might be capable of driving precocious activation of the zygotic genome, leading to embryonic lethality. To test this hypothesis, we performed single embryo RNA-seq at distinct nuclear cycles throughout zygotic genome activation (NC10, NC12, NC13, and NC14) in control and brat-mutant embryos. Our results conclusively demonstrated that in embryos lacking functional BRAT, Zelda target genes were not prematurely activated. Rather, these genes were expressed normally, but become significantly upregulated at nuclear cycle 14, when the division cycle slows. Our data support a model in which zygotic genome activation requires precise coordination between expression of reprogramming factors, such as Zelda, and the slowing of the cell cycle.
2022-06-17 | GSE197582 | GEO
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:The Drosophila TRIM-NHL protein Brain tumor (Brat) plays important roles during early embryogenesis, in cell fate decisions, during neurogenesis and in mature neurons. Brat is an RNA-binding protein and functions as translational repressor. However, which RNAs Brat regulates and how RNA-binding specificity is achieved, is unknown. Using RNA-Immunoprecipitation we identify Brat-bound mRNAs in Drosophila embryos and define a consensus binding motif. Microarrays were used to profile Brat-associated RNAs from fly embryos.
2015-11-13 | GSE71663 | GEO
Project description:Systematic discovery of cap-independent translation sequences in human and viral genomes
| PRJNA299626 | ENA