Functional analysis of FGF3 during zebrafish inner ear development

FGF3 has been involved in the development of the inner ear in a number of s pecies including mouse, chicken and Xenopus. Initial experiments using anti sense oligonucleotides in explants of chicken embryos indicated a role for FGF3 for proper formation of the otic vesicle (Represa et al., 1991). Howev er, mice carrying a mutant FGF3 allele exhibited normal formation of the ot ic vesicle and only showed defects during later differentiation of the inne r ear (Mansour et al, 1993). Implantation of beads incubated with FGF3 into Xenopus embryos led to the formation of ectopic vesicles (Lombardo et at., 1998). To further resolve the functions of FGF3 during inner ear developme nt we recently performed gain-of-function experiments in chicken embryos by ectopically expressing FGF3 via a Herpes simplex-derived viral vector (Ven drell et al., 2000). Embryos infected by the virus developed ectopic otic v esicles confirming the involvement of FGF3 during formation of the otic ves icle in avians. To further clarify the role of FGF3 during inner ear develo pment in vertebrates, we have now addressed its potential function in zebra fish.