A temporal window for signal activation dictates the dimensions of a nodal signaling domain
journal contributionposted on 22.09.2020, 10:06 by Antonius L van Boxtel, John E Chesebro, Claire Heliot, Marie-Christine Ramel, Richard K Stone, Caroline S Hill
Morphogen signaling is critical for the growth and patterning of tissues in embryos and adults, but how morphogen signaling gradients are generated in tissues remains controversial. The morphogen Nodal was proposed to form a long-range signaling gradient via a reaction-diffusion system, on the basis of differential diffusion rates of Nodal and its antagonist Lefty. Here we use a specific zebrafish Nodal biosensor combined with immunofluorescence for phosphorylated Smad2 to demonstrate that endogenous Nodal is unlikely to diffuse over a long range. Instead, short-range Nodal signaling activation in a temporal window is sufficient to determine the dimensions of the Nodal signaling domain. The size of this temporal window is set by the differentially timed production of Nodal and Lefty, which arises mainly from repression of Lefty translation by the microRNA miR-430. Thus, temporal information is transformed into spatial information to define the dimensions of the Nodal signaling domain and, consequently, to specify mesendoderm.
LeftyNodalmesendodermmiR-430morphogentemporal signal activation windowzebrafishAnimalsBiosensing TechniquesBody PatterningGene Expression Regulation, DevelopmentalLeft-Right Determination FactorsMicroRNAsNodal ProteinSmad2 ProteinZebrafishZebrafish ProteinsHillHPLM-ackGEP-ackCB-ackDevelopmental Biology06 Biological Sciences11 Medical and Health Sciences