Hedgehog signaling regulates dental papilla formation and tooth size during zebrafish odontogenesis.

Background: Intercellular communication by the hedgehog cell signaling pathway is necessary for tooth development throughout the vertebrates, but it remains unclear which specific developmental signals control cell behavior at different stages of odontogenesis. To address this issue, we have manipulated hedgehog activity during zebrafish tooth development and visualized the results using confocal microscopy.

Results: We first established that reporter lines for dlx2b, fli1, NF-κB, and prdm1a are markers for specific subsets of tooth germ tissues.

Comparison of acid mucin goblet cell distribution and Hox13 expression patterns in the developing vertebrate digestive tract.

The digestive tract of vertebrates is a complex organ system required for the digestion of food and the absorption of nutrients. The colon evolved as a water absorption organ essential for vertebrates to survive on land. In contrast to land vertebrates, the Chondrichthyes (sharks, skates and rays) are nearly iso-osmotic with their ocean environment and do not reabsorb water from food waste.