RESUMO
The terminal differentiation of adult stem cell progeny depends on transcriptional control. A dramatic change in gene expression programs accompanies the transition from proliferating spermatogonia to postmitotic spermatocytes, which prepare for meiosis and subsequent spermiogenesis. More than a thousand spermatocyte-specific genes are transcriptionally activated in early Drosophila spermatocytes. Here we describe the identification and initial characterization of dany, a gene required in spermatocytes for the large-scale change in gene expression. Similar to tMAC and tTAFs, the known major activators of spermatocyte-specific genes, dany has a recent evolutionary origin, but it functions independently. Like dan and danr, its primordial relatives with functions in somatic tissues, dany encodes a nuclear Psq domain protein. Dany associates preferentially with euchromatic genome regions. In dany mutant spermatocytes, activation of spermatocyte-specific genes and silencing of non-spermatocyte-specific genes are severely compromised and the chromatin no longer associates intimately with the nuclear envelope. Therefore, as suggested recently for Dan/Danr, we propose that Dany is essential for the coordination of change in cell type-specific expression programs and large-scale spatial chromatin reorganization.
Assuntos
Núcleo Celular/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/citologia , Drosophila melanogaster/genética , Regulação da Expressão Gênica , Proteínas Nucleares/metabolismo , Espermatócitos/citologia , Espermatócitos/metabolismo , Transcrição Gênica , Sequência de Aminoácidos , Animais , Pontos de Checagem do Ciclo Celular/genética , Forma do Núcleo Celular/genética , Cromatina/metabolismo , Cromossomos/metabolismo , Proteínas de Drosophila/química , Proteínas de Drosophila/genética , Fertilidade/genética , Genes de Insetos , Masculino , Meiose/genética , Mutação/genética , Membrana Nuclear/metabolismo , Proteínas Nucleares/química , Proteínas Nucleares/genética , Espermatogênese/genética , Frações Subcelulares/metabolismo , Testículo/citologia , Testículo/metabolismoRESUMO
The analysis of consequences resulting after experimental elimination of gene function has been and will continue to be an extremely successful strategy in biological research. Mutational elimination of gene function has been widely used in the fly Drosophila melanogaster. RNA interference is used extensively as well. In the fly, exceptionally precise temporal and spatial control over elimination of gene function can be achieved in combination with sophisticated transgenic approaches and clonal analyses. However, the methods that act at the gene and transcript level cannot eliminate protein products which are already present at the time when mutant cells are generated or RNA interference is started. Targeted inducible protein degradation is therefore of considerable interest for controlled rapid elimination of gene function. To this end, a degradation system was developed in yeast exploiting TIR1, a plant F box protein, which can recruit proteins with an auxin-inducible degron to an E3 ubiquitin ligase complex, but only in the presence of the phytohormone auxin. Here we demonstrate that the auxin-inducible degradation system functions efficiently also in Drosophila melanogaster. Neither auxin nor TIR1 expression have obvious toxic effects in this organism, and in combination they result in rapid degradation of a target protein fused to the auxin-inducible degron.