Fig. 8. Ch-Ac and Ch-Sm concentrate in the posterior region of migrating cells. Cells were pulsed with 75 nM cAMP (final concentration) as in Fig. 9. At the times of maximum cAR1 concentration (see text), cells were washed and placed on a coverslip and allowed to migrate towards a pipette containing 10 µM cAMP, as in Fig. 7. Micrographs of cells expressing GFP-myosins were taken while the cells were under observation so the direction of movement was known. The localization of Ch-Sm was determined by indirect immunofluorescence of fixed cells and the direction of movement inferred from the orientation of the pseudopods. The cells shown are typical. All were moving from right to left. GFP-Dd-Wt-AX3, AX3 cell expressing GFP-Dd-Wt; GFP-Dd-Wt, HS1 cell expressing GFP-Dd-Wt; GFP-Ch-Ac, HS1 cell expressing GFP-Ch-Ac; Ch-Sm, HS1 cell expressing Ch-Sm.