A recently discovered transcription factor, Sp8, is required for limb development and neural tube closure. It is also expressed in specific domains of the medial telencephalon at various points during embryonic development. We believe that this gene could be important in defining the developing olfactory bulbs, as well as the olfactory epithelium. These regions represent some of the few known instances of adult neurogenesis. My project will investigate the role of Sp8 in the telencephalon by using conditional mutant (floxed) Sp8 alleles. These will allow me to recombine out the Sp8 coding sequence, thereby inactivating Sp8 expression, within specific areas at specific times in development. Using a Foxg1-cre allele to drive telencephalic cre expression, I will investigate whether Sp8 is required for olfactory bulb formation, as well as generation of the olfactory epithelium. I will also use a Foxg1-tTA allele as a component of a tetracycline-inducible system to turn on cre expression within the telencephalon. With this technique, I can control the time at which Sp8 is inactivated. This will allow us to investigate later roles of Sp8 during embryonic development, as well as the possible adult requirement for Sp8 in generation of olfactory bulb interneurons.