Shh, Bmp-2, Bmp-4 and Fgf-8 are associated with initiation and patterning of mouse tongue papillae. |
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Authors: | H S Jung V Oropeza I Thesleff |
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Institution: | Developmental Biology Programme, Institute of Biotechnology, Viikki Biocentre, P.O. Box 56, FIN-00014, University of Helsinki, Helsinki, Finland. hsjung@operoni.helsinki.fi |
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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. |
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