Fig. 4. Fragmentation of migrating PGCs is more frequently observed in the presence of FGFR inhibitor. (A) Fragmentation of a PGC (arrowed) is shown from a time-lapse movie of an E9.5 OCT4PE:GFP embryo slice treated with 1 µM SU5402. The GFP-labeled PGC (arrow), started to fragment at frame 62, corresponding to 434 minutes from the beginning of movie. This time of onset of fragmentation is represented by the single dot with the red circle in D. (B) A fragmented PGC is stained by the apoptotic cell marker anti-cleaved caspase-3. (C) Pictures from frame 20 of a control and FGFR inhibitor-treated slice. Fragments of PGCs are observed in the dorsal body wall of the 1 µM FGFR inhibitor-treated slice (dashed circle). No fragmented PGCs are observed in the control slice. (D) Timing of onset of fragmentation of PGCs, taken from a total of seven movies for each treatment. The onset of fragmentation of each PGC is represented as a dot. Fragmentation of the arrowed PGC in A started at frame 62, and is represented by the single dot with the red circle. Inset shows the average number of fragmentations in a single movie (fragmented germ cells/movie). Data are means±s.e.m. from three separate experiments (n=7). Means with different letters were significantly different (P<0.05) from each other. Scale bars: 10 µm for A,B; 100 µm for C.