Evidence for the role of the enamel knot as a control center in mammalian tooth cusp formation: non-dividing cells express growth stimulating Fgf-4 gene.

摘要: The main morphological features of the mammalian tooth crown are cusps, but developmental mechanisms that cause formation cusps unknown. Tooth cusp commences at cap-stage with appearance enamel knot, which is a cluster non-dividing epithelial cells. In this study, knot was first seen in embryonic mice molar teeth onset cap-stage. Later development, secondary structures were observed tips and their corresponded to individual morphology. Comparisons pattern cell proliferation mouse molars expression fibroblast growth factor-4 (Fgf-4) gene revealed Fgf-4 mRNA strictly localized cells knot. However, when FGF-4 protein introduced onto isolated dental tissues vitro, it stimulated both mesenchymal Based on these results, we suggest may control morphogenesis by concurrently stimulating (via synthesis) directing folding slopes (by not proliferating itself).