The Paramount Role of Drosophila melanogaster in the Study of Epigenetics: From Simple Phenotypes to Molecular Dissection and Higher-Order Genome Organization
Résumé
Drosophila melanogaster has played a paramount role in epigenetics, the study of changes
in gene function inherited through mitosis or meiosis that are not due to changes in the DNA sequence.
By analyzing simple phenotypes, such as the bristle position or cuticle pigmentation, as
read-outs of regulatory processes, the identification of mutated genes led to the discovery of major
chromatin regulators. These are often conserved in distantly related organisms such as vertebrates
or even plants. Many of them deposit, recognize, or erase post-translational modifications on histones
(histone marks). Others are members of chromatin remodeling complexes that move, eject, or
exchange nucleosomes. We review the role of D. melanogaster research in three epigenetic fields:
Heterochromatin formation and maintenance, the repression of transposable elements by piRNAs,
and the regulation of gene expression by the antagonistic Polycomb and Trithorax complexes. We
then describe how genetic tools available in D. melanogaster allowed to examine the role of histone
marks and show that some histone marks are dispensable for gene regulation, whereas others play
essential roles. Next, we describe how D. melanogaster has been particularly important in defining
chromatin types, higher-order chromatin structures, and their dynamic changes during development.
Lastly, we discuss the role of epigenetics in a changing environment.
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