A unified mechanism for the control of < i > Drosophila < /i > wing growth by the morphogens Decapentaplegic and Wingless

by Myriam Zecca, Gary Struhl Development of theDrosophila wing —a paradigm of organ development—is governed by 2 morphogens, Decapentaplegic (Dpp, a BMP) and Wingless (Wg, a Wnt). Both proteins are produced by defined subpopulations of cells and spread outwards, forming gradients that control gene expression and cell pattern as a function of concentration. They also control growth, but how is unknown. Most studies have focused on Dpp and yielded disparate models in which cells throughout the wing grow at similar rates in response to the grade or temporal change in Dpp concentration or to the different amounts of Dpp “equalized” by molecular or mec hanical feedbacks. In contrast, a model for Wg posits that growth is governed by a progressive expansion in morphogen range, via a mechanism in which a minimum threshold of Wg sustains the growth of cells within the wing and recruits surrounding “pre-wing” cells to grow and enter the wing. This mechanism depends on the capacity of Wg to fuel the autoregulation ofvestigial (vg) —the selector gene that specifies the wing state—both to sustainvg expression in wing cells and by a feed-forward (FF) circuit of Fat (Ft)/Dachsous (Ds) protocadherin signaling to inducevg expression in neighboring pre-wing cells. Here, we have subjected Dpp to the same experimental tests used to elucidate the Wg model and find that it behaves indistinguishably. Hence, we posit that both morphogens act together, via a common mechanism, to cont...
Source: PLoS Biology: Archived Table of Contents - Category: Biology Authors: Source Type: research