13-P079 Heparan sulphotransferases are regulators of mammalian axon guidance

These are consistent with proposals that Fgf10 expression in the developing sensory tissues is required to induce non-sensory development. To determine the otic epithelial functions of Fgf3 and Fgf10, we generated double conditional mutants using TgPax2Cre, and found that as expected, both genes play roles in semicircular canal morphogenesis. Unexpectedly, these genes also appear to have redundant roles in cochlear morphogenesis. We will describe progress in determining the molecular mechanisms by which these FGFs control morphogenesis, as well as a new approach to controlling Fgf3 expression with doxycyline administration that should enable detailed analysis of otic morphogenesis, both in vivo and in culture.