Fig. 3. Mutant S13A-1 cells retract anterior pseudopods and extend lateral pseudopods in a manner similar to that of wild-type JH10 cells. Retraction of the original anterior pseudopod and extension of a new lateral pseudopod over a 24 second period for a representative JH10 (A) and S13A (B) cell imaged through differential interference contrast optics. a, original anterior pseudopod, at time zero, and new anterior pseudopod at 24 seconds; u, uropod. Arrows indicate direction of retraction of original anterior pseudopod and direction of expansion of new lateral pseudopod for both cell types. Time is indicated in seconds in upper left hand corners of panels. Similar results were obtained for cells of strains WT-res, S13A-2 and S13A-3.