Fig. 5. Hippocampal neurons ectopically expressing P-Rex1 show enlarged growth cones with prominent F-actin accumulation. Embryonic rat hippocampal cells were transiently transfected at 7 d.i.v. with plasmids encoding HA-P-Rex1. At 9 d.i.v., cells were co-stained with HA antibodies (red or green) and either (A) Alexa Fluor 594-conjugated phalloidin (green) or (B) Tau1 (red) antibodies. (A) Representative images of differentiated neurons (upper row), with higher-magnification images of the boxed areas (1, 2) shown in the two lower rows; growth cones are outlined. The relative intensity of F-actin staining is shown on the left in glowover images, in which blue indicates high-intensity staining (see scale). Scale bars: 10 µm. (B) Co-localisation of HA-P-Rex1 and Tau1. In the merged image, axon is indicated by an arrowhead. Scale bar: 20 µm. (C) The fold increase in growth cone area in HA-P-Rex1 or HA-P-Rex1N relative to mock-transfected cells. Axonal and dendritic growth cones were identified by Tau1 and MAP2 staining, respectively. Thirty cells were scored for each construct for two independent transfections. Bars indicate the mean ± s.e.m. of the growth cone area; ^*P<0.05.