THE INITIAL EVIDENCE FOR HEDGEHOG SIGNALING INVOLVED IN THE DIFFERENTIATION OF MECHANORECEPTORS AND ELECTRORECEPTORS IN THE LATERAL LINE SYSTEM IN SIBERIAN STURGEON

The lateral line system of some amphibians, all chondrichthyan and non-neopterygian fish is consisted of mechanoreceptors and electroreceptors that are originated from lateral line placodes. However, the molecular mecha-nism of mechanoreceptor and electroreceptor differentiation remains unclear. Hedgehog is a critical morphogen for pattern formation and stem cell differentiation of multiple organs. In this study, we investigated the relationship between hedgehog signaling and the differentiation of neuromast and ampullary organ in Siberian sturgeon. We found dynamic expression of Shh and Patched1 via the transcriptome analysis in regenerating neuromast and ampullary organ. Furthermore, inhibiting hedgehog signaling by cyclopamine from stage 29 to stage 37 reduced the number of ampullary organs specifically. In addition, cyclopamine repressed the expression of Shh, Patched1, Smoothened, and Gli2 in the ventral region of head. These results indicated that hedgehog signaling was related with the development ampullary organ in Siberian sturgeon.