Fig. 5. Biosynthetic routes of Syt I and Syt II. RBL cells, transiently transfected with Syt II (a-c) or T7-Syt I (d-g) cDNA, were grown on glass coverslips for 1 hour (a-f) or 5 hours (g) and then incubated for 2 hours at 20°C (a-f) or for 1 hour at 4°C in the presence of monoclonal antibodies directed against T7 (1 µg/ml) (g). Cells were subsequently transferred to 37°C (time zero) and incubated for the indicated time periods. Cells were stained with polyclonal antibodies directed against C2A-Syt IX (a-c) or with monoclonal antibodies directed against T7 (d-f) followed by Cy3-conjugated secondary antibodies. Cells were visualized by laser confocal microscopy. Bar, 5 µm.