Dynamics of placodal lineage development revealed by targeted transgene expression.

Examination of the expression pattern of the winged-helix transcription factor BF-1 outside of the neural tube in mouse embryos suggests that BF-1 is restricted to a population of cells that gives rise to the ectodermal placodes and their derivatives. Within the sensory cranial nerve ganglia, the expression of BF-1 distinguishes cells that arise from the placodes from those derived from the neural crest. Expression of a lacZ transgene targeted to the BF-1 locus was used to follow the placodal lineage during mouse development. Analysis of placodal development in mice with a targeted deletion of BF-1 reveals that, although BF-1 is required for proliferation of the cells arising from the nasal placode, it is not required for the proliferation, survival, or both, of placode-derived cells in the sensory cranial nerve ganglia. Dev Dyn 1999;215:332-343.