PrP does not significantly reduce death of cerebellar granule neurons induced by exogenous Bax. (A-D) Representative fluorescence images of cerebellar granule neurons from Prn-p0/0mice transfected with plasmids encoding EGFP and mouse Bax. Four days after transfection, cultures were stained with DAPI, and EGFP-positive neurons were scored as healthy (A, B) or apoptotic (C, D) based on morphological criteria. These criteria included the distribution of EGFP in the soma and neurites, and the appearance of DAPI staining in the nucleus (see text). (E) CGNs cultured from Prn-p+/+ or Prn-p0/0pups were transfected with plasmids encoding Bax and EGFP. Cultures were fixed and stained with DAPI either 8 or 16 hours after transfection, and scored for apoptotic morphology. Data represent the mean ± SEM from at least three independent experiments. The difference between Prn-p0/0and Prn-p+/+ neurons did not reach statistical significance at either time point (p > 0.05).