Long Range Dpp Gradient Formation
Decapentaplegic (Dpp) is a key morphogen which is expressed in a stripe of cells along the anteriorposterior (A-P) boundary of the Drosophila wing imaginal discs and diffuses along the A-P axis forming, at steady-state, a "quasi exponential" profile.
The mechanisms by which this profile is formed has however long been controversal and two distinct mechanisms involving Dpp receptors have been proposed: Receptor-Mediated Transcytosis (RMT) and Restricted Extracellular Diffusion (RED).
In a recent paper (for more details click here), we developed a rigorous theoretical model which involves three Dpp components: extracellular Dpp, receptor-bound Dpp and internalized Dpp. Providing a different parameter choice, this model allows to describe both the RMT and RED mechanism. Comparing our analytical model to wild-type and receptor mutant clone experimental data, we conclude that (1) the RMT mechanism is not consistent with our experimental data (2) a RED mechanism where most of the Dpp is unbound to the receptor leads to the expected Dpp profiles.
Schwank G, Dalessi S, Yang SF, Yagi R, de Lachapelle AM, Affolter M, Bergmann S, Basler K
Formation of the long range Dpp morphogen gradient.
PLoS Biol: 2011 Jul, 9(7);e1001111
[PubMed:21814489]
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