Requirements of high levels of Hedgehog signaling activity for medial-region cell fate determination in Drosophila legs: identification of pxb, a putative Hedgehog signaling attenuator gene repressed along the anterior-posterior compartment boundary.
We show that high levels of Hedgehog signaling activity are essential for medial-region patterning in Drosophila legs. In mid-to-late third instar leg discs, high levels of Hedgehog signals repress the transcription of pxb, a newly identified gene encoding a transmembrane protein expressed specifically in the anterior compartment. Misexpression experiments indicate that Pxb may serve as a Hedgehog signaling attenuator capable of acting prior to Hedgehog-Patched interactions, suggesting that Hedgehog signaling in leg discs includes a pxb-repression-mediated positive feedback loop. RNA interference and clonal analysis show that neither Wingless nor Decapentaplegic signaling is required for pxb repression but high levels of Wingless signaling activity are essential for patterning in the leg ventral medial region.
Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Japan.
Mikiko
M
Inaki
Tetsuya
T
Kojima
Ryu
R
Ueda
Kaoru
K
Saigo
D000595:Amino Acid Sequence; D000818:Animals; D019521:Body Patterning / Q000235:genetics; D004330:Drosophila / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D005246:Feedback; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D017930:Genes, Reporter; D053823:Hedgehog Proteins; D007763:Lac Operon; D007866:Leg; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D011956:Receptors, Cell Surface; D015398:Signal Transduction; D051155:Wnt1 Protein
D029721:Drosophila Proteins; D053823:Hedgehog Proteins; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D011956:Receptors, Cell Surface; D051155:Wnt1 Protein; C064196:dpp protein, Drosophila; C070844:ptc protein, Drosophila; C074622:wg protein, Drosophila; C077245:hh protein, Drosophila