Dependence of Drosophila wing imaginal disc cytonemes on Decapentaplegic.
The anterior/posterior (A/P) and dorsal/ventral (D/V) compartment borders that subdivide the wing imaginal discs of Drosophila third instar larvae are each associated with a developmental organizer. Decapentaplegic (Dpp), a member of the transforming growth factor-beta (TGF-beta) superfamily, embodies the activity of the A/P organizer. It is produced at the A/P organizer and distributes in a gradient of decreasing concentration to regulate target genes, functioning non-autonomously to regulate growth and patterning of both the anterior and posterior compartments. Wingless (Wg) is produced at the D/V organizer and embodies its activity. The mechanisms that distribute Dpp and Wg are not known, but proposed mechanisms include extracellular diffusion, successive transfers between neighbouring cells, vesicle-mediated movement, and direct transfer via cytonemes. Cytonemes are actin-based filopodial extensions that have been found to orient towards the A/P organizer from outlying cells. Here we show that in the wing disc, cytonemes orient towards both the A/P and D/V organizers, and that their presence and orientation correlates with Dpp signalling. We also show that the Dpp receptor, Thickveins (Tkv), is present in punctae that move along cytonemes. These observations are consistent with a role for cytonemes in signal transduction.
Hsiung
Frank
F
Department of Biochemistry and Biophysics, University of California, San Francisco, California 94143, USA.
Ramirez-Weber
Felipe-Andrès
FA
Iwaki
D David
DD
Kornberg
Thomas B
TB
D000199:Actins / Q000378:metabolism; D000818:Animals; D019521:Body Patterning; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D007814:Larva / Q000254:growth & development; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011554:Pseudopodia / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism; D015398:Signal Transduction; D014921:Wings, Animal / Q000166:cytology* / Q000254:growth & development* / Q000378:metabolism
D000199:Actins; D029721:Drosophila Proteins; D011956:Receptors, Cell Surface; C064196:dpp protein, Drosophila; C090169:tkv protein, Drosophila; D017346:Protein Serine-Threonine Kinases