The Histone H3 Acetylase dGcn5 Is a Key Player in Drosophila melanogaster Metamorphosis

Laboratory of Drosophila Genetics and Epigenetics, Department of Developmental Biology, CNRS URA 2578, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France.
Molecular and Cellular Biology (Impact Factor: 4.78). 10/2005; 25(18):8228-38. DOI: 10.1128/MCB.25.18.8228-8238.2005
Source: PubMed


Although it has been well established that histone acetyltransferases (HATs) are involved in the modulation of chromatin structure and gene transcription, there is only little information on their developmental role in higher organisms. Gcn5 was the first transcription factor with HAT activity identified in eukaryotes. Here we report the isolation and characterization of Drosophila melanogaster dGcn5 mutants. Null dGcn5 alleles block the onset of both oogenesis and metamorphosis, while hypomorphic dGcn5 alleles impair the formation of adult appendages and cuticle. Strikingly, the dramatic loss of acetylation of the K9 and K14 lysine residues of histone H3 in dGcn5 mutants has no noticeable effect on larval tissues. In contrast, strong cell proliferation defects in imaginal tissues are observed. In vivo complementation experiments revealed that dGcn5 integrates specific functions in addition to chromosome binding and acetylation. Surprisingly, a dGcn5 variant protein with a deletion of the bromodomain, which has been shown to recognize acetylated histones, appears to be fully functional. Our results establish dGcn5 as a major histone H3 acetylase in Drosophila which plays a key role in the control of specific morphogenetic cascades during developmental transitions.

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Available from: Christophe Antoniewski, Oct 01, 2015
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    • "In previous studies the regulation of chromatin structure and transcription activation by HAT complexes, such as ATAC and SAGA, have been extensively investigated (Lee and Workman, 2007; Nagy and Tora, 2007). It has been shown that GCN5 HAT, the common catalytic subunit of the dATAC and dSAGA multisubunit HAT complexes could acetylate both histone and non-histone proteins (Carre et al., 2005). The latter function of ATAC has been less known, although recent studies have shown that GCN5-containing ATAC complex localizes to the mitotic spindles and mediate acetylation of Cyclin A at specific lysine residues which triggers its degradation (Mateo et al., 2009; Orpinell et al., 2010). "
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    ABSTRACT: The molting during Drosophila development is tightly regulated by the ecdysone hormone. Several steps of the ecdysone biosynthesis have been already identified but the regulation of the entire process has not been clarified yet. We have previously reported that dATAC histone acetyltransferase complex is necessary for the steroid hormone biosynthesis process. To reveal possible mechanisms controlled by dATAC we made assumptions that either dATAC may influence directly the transcription of Halloween genes involved in steroid hormones biosynthesis or it may exert an indirect effect on it by acetylating the Ftz-F1 transcription factor which regulates the transcription of steroid converting genes. Here we show that the lack of dATAC complex results in increased mRNA level and decreased protein level of Ftz-F1. In this context, decreased mRNA and increased protein levels of Ftz-F1 were detected upon treatment of Drosophila S2 cells with histone deacetylase inhibitor trichostatin A. We showed that Ftz-F1, the transcriptional activator of Halloween genes, is acetylated in S2 cells. In addition, we found that ecdysone biosynthetic Halloween genes are transcribed in S2 cells and their expression can be influenced by deacetylase inhibitors. Furthermore, we could detect H4K5 acetylation at the regulatory regions of disembodied and shade Halloween genes, while H3K9 acetylation is absent on these genes. Based on our findings we conclude that the dATAC HAT complex might play a dual regulatory role in Drosophila steroid hormone biosynthesis through the acetylation of Ftz-F1 protein and the regulation of histone H4 most probably the H4K5 acetylation at the promoters of Halloween genes. Copyright © 2015 Elsevier Inc. All rights reserved.
    Developmental Biology 05/2015; 404(1). DOI:10.1016/j.ydbio.2015.04.020 · 3.55 Impact Factor
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    • "The complexes include distinct Ada2 relatives: SAGA contains the Ada2b protein, whereas ATAC contains the Ada2a protein (Kusch et al, 2003; Muratoglu et al, 2003). Gcn5 was found to be essential for in vivo acetylation of larval polytene chromosomes at positions lysine 9 (K9)/K14 of histone H3 and K5/K12 of histone H4 (Carre et al, 2005; Ciurciu et al, 2006). In addition, mutations in the Ada2b gene result in a loss of acetylation of residues H3-K9/K14, whereas mutations in the Ada2a gene only affect acetylation of residues H4-K5/K12 (Qi et al, 2004; Pankotai et al, 2005; Ciurciu et al, 2006). "
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    • "For protein analysis, equal amounts of proteins from total extract, supernatant, or immunoprecipitate samples were boiled in Laemmli buffer and loaded on 12% SDS/PAGE. After transfer onto nitrocellulose membrane and Ponceau staining, membranes were blocked in 5% milk, 1X PBS, 0.1% Tween, and incubated overnight with anti-GFP (1∶2000; Roche), anti-Mbf1 (1∶10000; [28], anti-Ago1 (1∶1000; Abcam ab5070), anti-HA (1∶1000; Roche) or anti-γ-Tubulin (1∶2000; Sigma) antibodies. anti-Dcr-1, anti-Dcr-2 and anti-Ago2 were used at 1∶1000 (a kind gift of Mikiko C. Siomi). "
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    ABSTRACT: Defects in miRNA biogenesis or activity are associated to development abnormalities and diseases. In Drosophila, miRNAs are predominantly loaded in Argonaute-1, which they guide for silencing of target RNAs. The miRNA pathway overlaps the RNAi pathway in this organism, as miRNAs may also associate with Argonaute-2, the mediator of RNAi. We set up a gene construct in which a single inducible promoter directs the expression of the GFP protein as well as two miRNAs perfectly matching the GFP sequences. We show that self-silencing of the resulting automiG gene requires Drosha, Pasha, Dicer-1, Dicer-2 and Argonaute-2 loaded with the anti-GFP miRNAs. In contrast, self-silencing of the automiG gene does not involve Argonaute-1. Thus, automiG reports in vivo for both miRNA biogenesis and Ago-2 mediated silencing, providing a powerful biosensor to identify situations where miRNA or siRNA pathways are impaired. As a proof of concept, we used automiG as a biosensor to screen a chemical library and identified 29 molecules that strongly inhibit miRNA silencing, out of which 5 also inhibit RNAi triggered by long double-stranded RNA. Finally, the automiG sensor is also self-silenced by the anti-GFP miRNAs in HeLa cells and might be easily used to identify factors involved in miRNA biogenesis and silencing guided by perfect target complementarity in mammals.
    PLoS ONE 09/2013; 8(9):e74296. DOI:10.1371/journal.pone.0074296 · 3.23 Impact Factor
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