Fig. 2. KIF3A protein colocalizes with tau mRNA in RNP granules. (A) Confocal image analysis of KIF3A protein localization in differentiated P19 cells. (a) Phase image of differentiated P19 cell. (b) Expression of GFP-tau protein. (c) Staining with KIF3A antibodies. (d) In situ hybridization analysis with the GFP probe (which detects the transfected tau mRNA). (e) Merged confocal image of b, c and d (x2500 magnification). The solid arrowheads denote axons, empty arrowheads denote dendrites and small solid curved arrowheads denote neuronal cell bodies. Bar, 10 µm. (B) Confocal merged image of a growth cone. The enlarged merged image from the cell shown in A. The merged staining includes the GFP-tau fluorescence (green), KIF3A immunostaining (cyan) and GFP in situ hybridization (red), yielding a white colocalization. Aggregation of tau granules is marked by a solid arrowhead. A non-localized KIF3A signal (cyan) is marked by an asterisk. Bar, 1 µm (x20000 magnification).