title: Shh, Bmp-2, Bmp-4 and Fgf-8 are associated with initiation and patterning of mouse tongue papillae.
abstract: Spacing patterns are of fundamental importance in various repeated structures which develop at regular intervals such as feathers, teeth and insect ommatidia. The mouse tongue develops a regular papilla pattern and provides a good model to study pattern formation. We examined the expression patterns of the signalling molecules, sonic hedgehog (Shh), bone morphogenetic proteins -2 and -4 (Bmp-2 and Bmp-4), and fibroblast growth factor-8 (Fgf-8) in mouse embryos between E 10.5 and 15. We show that all four genes are expressed uniformly in the tongue epithelium between E 10.5 and 11. At E 13, before morphologically detectable gustatory papillae initiation, Shh, Bmp-2 and Bmp-4 expression segregates into discrete spots, whereas, Fgf-8 is downregulated. At E 14, small eminences in the anterior part of the tongue are the first morphological indications of fungiform papillae, and they express Shh and Bmp-2, whereas, Bmp-4 is almost absent in the tongue. We conclude that these conserved signalling molecules are associated with the initiation and early morphogenesis of the tongue papillae.
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000032:analysis / Q000378:metabolism*; D004801:Eosine Yellowish-(YS) / Q000378:metabolism; D051524:Fibroblast Growth Factor 8; D005346:Fibroblast Growth Factors / Q000032:analysis / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D053823:Hedgehog Proteins; D006416:Hematoxylin / Q000378:metabolism; D017403:In Situ Hybridization; D051379:Mice; D008808:Mice, Inbred CBA; D008815:Mice, Inbred Strains; D011506:Proteins / Q000032:analysis / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors; D014059:Tongue / Q000196:embryology*; D015534:Trans-Activators; D016212:Transforming Growth Factor beta