Pointed regulates an eye-specific transcriptional enhancer in the Drosophila hedgehog gene, which is required for the movement of the morphogenetic furrow.
Drosophila development depends on stable boundaries between cellular territories, such as the embryonic parasegment boundaries and the compartment boundaries in the imaginal discs. Patterning in the compound eye is fundamentally different: the boundary is not stable, but moves (the morphogenetic furrow). Paradoxically, Hedgehog signaling is essential to both: Hedgehog is expressed in the posterior compartments in the embryo and in imaginal discs, and posterior to the morphogenetic furrow in the eye. Therefore, uniquely in the eye, cells receiving a Hedgehog signal will eventually produce the same protein. We report that the mechanism that underlies this difference is the special regulation of hedgehog (hh) transcription through the dual regulation of an eye specific enhancer. We show that this enhancer requires the Egfr/Ras pathway transcription factor Pointed. Recently, others have shown that this same enhancer also requires the eye determining transcription factor Sine oculis (So). We discuss these data in terms of a model for a combinatorial code of furrow movement.
Rogers
Edward M
EM
Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
Brennan
Catherine A
CA
Mortimer
Nathan T
NT
Cook
Summer
S
Morris
Andrea R
AR
Moses
Kevin
K
D000818:Animals; D019521:Body Patterning; D004268:DNA-Binding Proteins / Q000502:physiology*; D004330:Drosophila / Q000196:embryology / Q000254:growth & development; D029721:Drosophila Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D004625:Embryo, Nonmammalian; D004742:Enhancer Elements, Genetic; D066246:ErbB Receptors / Q000378:metabolism; D005123:Eye / Q000196:embryology* / Q000254:growth & development; D053823:Hedgehog Proteins; D009024:Morphogenesis / Q000235:genetics*; D009068:Movement; D009419:Nerve Tissue Proteins / Q000502:physiology*; D011494:Protein Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D018010:Receptors, Invertebrate Peptide / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D053823:Hedgehog Proteins; D009419:Nerve Tissue Proteins; D011518:Proto-Oncogene Proteins; D018010:Receptors, Invertebrate Peptide; D014157:Transcription Factors; C083884:pnt protein, Drosophila; C077245:hh protein, Drosophila; D011494:Protein Kinases; C066532:Egfr protein, Drosophila; D066246:ErbB Receptors