FGF signaling refines Wnt gradients to regulate patterning of taste papillae

• DOI: 10.1242/dev.148080
• Publication Date: 2017-05-16T00:10:23Z
• Authors: Michaela Prochazkova; Teemu J. Häkkinen; Jan Prochazka; Frantisek Spoutil; Andrew H. Jheon; Youngwook Ahn; Robb Krumlauf; Jukka Jernvall; Ophir D. Klein
• Keywords: Male; Mice, Transgenic; Protein Serine-Threonine Kinases; Models, Biological; Wnt; Mice; 03 medical and health sciences; Tongue; Pregnancy; FGF; Animals; Computer Simulation; Hedgehog Proteins; Wnt Signaling Pathway; Adaptor Proteins, Signal Transducing; Body Patterning; Mice, Knockout; 0303 health sciences; Intracellular Signaling Peptides and Proteins; Membrane Proteins; Taste Buds; Taste papilla; Bone Morphogenetic Proteins; Female; Fibroblast Growth Factor 10

The patterning of repeated structures is a major theme in developmental biology, and the interrelationship between spacing and size of such structures is an open question. Fungiform papillae are repeated epithelial structures that house taste buds on the anterior tongue. Here, we report that FGF signaling is a critical regulator of fungiform papillae development. We found that mesenchymal FGF10 controls the size of the papillary area, while overall patterning remains unchanged. Our results show that FGF signaling negatively affects the extent of canonical Wnt signaling, which is the main activation pathway during fungiform papillae development, but this effect does not occur at the level of gene transcription. Rather, our experimental data together with computational modeling indicate that FGF10 modulates the range of Wnt effects, likely via induction of Sostdc1 expression. We suggest that modification of the reach of Wnt signaling could be due to local changes in morphogen diffusion, representing a novel mechanism in this tissue context, and we propose that this phenomenon might be involved in a broader array of mammalian developmental processes.