Fig. 7. CASK is present in mobile vesicle-like structures in OLs. (A,B) OL progenitors in culture were transfected with a CASK-EGFP fusion protein and OLs were analyzed by confocal microscopy after 3 days. Images were converted to grayscale mode and colors inverted; CASK-EGFP is shown in black. (B) Time-lapse analysis of CASK-EGFP in a representative OL process segment shows that the protein is present in mobile puncta (arrows). Images were collected every 8 seconds. (C) OLs in culture labeled with anti-CASK Ab (green) and anti-dynein Ab (red) were analyzed by confocal microscopy and colocalization in OL processes was quantified for 280 puncta in eight representative cells from two independent cultures. Arrows indicate a fluorescent punctum positive for CASK and dynein. Bars, 10 µm (A,C), 2 µm (B).