Tissue specificity of hedgehog repression by the Polycomb group during Drosophila melanogaster development.
During embryogenesis and wing disc morphogenesis in Drosophila, different developmental mechanisms are used along the antero-posterior (A-P) axis. The establishment of antero-posterior polarity requires the secreted protein Hedgehog, which is only expressed in P compartments and which is a key effector of the Engrailed transcription factor. At the same time, it is essential that both engrailed and hedgehog (hh) remain in a repressed state in A compartments. In this article, we show that hh is maintained in a repressed state by the Polycomb group (PcG) chromatin proteins. We show that this process takes place during embryogenesis through two genomic elements that display genetic properties of a PRE. Interestingly, hh expression is not regulated by PcG genes in salivary glands, although at the same developmental stage PcG proteins repress hh in the A compartment of the wing disc. In addition, no PcG binding sites were found on polytene chromosomes, neither within hh transgenic constructs nor at the hh endogenous locus. Together, these results suggest that hh repression by the PcG acts in a tissue-specific manner.
Chanas
Grégory
G
Institut de Génétique Humaine (IGH-CNRS UPR 1142) 141 rue de la Cardonille 34396 Montpellier France.
Maschat
Florence
F
D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D019521:Body Patterning / Q000235:genetics; D004247:DNA / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D053823:Hedgehog Proteins; D006657:Histones / Q000378:metabolism; D009928:Organ Specificity; D063150:Polycomb Repressive Complex 1; D012097:Repressor Proteins / Q000378:metabolism*; D012469:Salivary Glands / Q000254:growth & development / Q000378:metabolism
D029721:Drosophila Proteins; D053823:Hedgehog Proteins; D006657:Histones; C066770:Pc protein, Drosophila; D012097:Repressor Proteins; C077245:hh protein, Drosophila; D004247:DNA; D063150:Polycomb Repressive Complex 1