Requirement for engrailed and invected genes reveals novel regulatory interactions between engrailed/invected, patched, gooseberry and wingless during Drosophila neurogenesis.
During neurogenesis, the transmembrane protein Patched (Ptc) promotes a wingless (wg)-mediated specification of a neuronal precursor cell, NB4-2, by repressing gooseberry (gsb). In this study, novel interactions of these genes with engrailed (en) and invected (inv) during neurogenesis have been uncovered. While in row 4 cells Ptc represses gsb and wg, in row 5 cells en/inv relieve Ptc repression of gsb by a non-autonomous mechanism that does not involve hedgehog (hh). This differential regulation of gsb leads to the specification of NB5-3 and NB4-2 identities to two distinct neuroblasts. The uncoupling of the ptc-gsb regulatory circuit also enables gsb to promote Wg expression in row 5 cells. Our results suggest that the en/inv-->ptc-->gsb-->wg pathway uncovered here and the hh-->wg are distinct pathways that function to maintain wild-type level of Wg. Our results also indicate that Hh is not the only ligand for Ptc and similarly Ptc is not the only receptor for Hh.
Bhat
K M
KM
Department of Molecular Biology, Princeton University, New Jersey 08544, USA. KBhat@crick.princeton.edu
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D000818:Animals; D030801:Animals, Genetically Modified; D004330:Drosophila / Q000196:embryology* / Q000235:genetics; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian; D004627:Embryonic Induction; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics; D018398:Homeodomain Proteins / Q000096:biosynthesis*; D006720:Homozygote; D006358:Hot Temperature; D019476:Insect Proteins / Q000096:biosynthesis*; D008565:Membrane Proteins / Q000096:biosynthesis*; D016296:Mutagenesis; D009420:Nervous System / Q000166:cytology / Q000196:embryology*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*; D011956:Receptors, Cell Surface / Q000096:biosynthesis; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D014157:Transcription Factors / Q000096:biosynthesis*; D051155:Wnt1 Protein; D001616:beta-Galactosidase / Q000096:biosynthesis
D029721:Drosophila Proteins; C063459:En protein, Drosophila; D018840:HSP70 Heat-Shock Proteins; D018398:Homeodomain Proteins; D019476:Insect Proteins; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D051155:Wnt1 Protein; C087983:inv protein, Drosophila; C070844:ptc protein, Drosophila; C074622:wg protein, Drosophila; D001616:beta-Galactosidase