Movie 2 (related to Fig. 2A-C).

Primitive microglial cells die in the midbrain optic tectum of a Slc7a7-deficient zebrafish larva by 3 dpf. Time-lapse confocal imaging of a 3 dpf Tg(mpeg1:gal4; uas:Nfsb-mCherry) larva injected with the slc7a7-sp22 morpholino at the 1-2 cell stage, and imaged in parallel with the control Mo-injected larva shown in Movie 1, within the same glass-bottomed dish. Dorsal view, rostral to the top (maximum projection from a z-stack); time step = 3 min. Selected time points of this movie are shown in Fig. 2C. The macrophages / microglial cells tracked by a white and a yellow arrowhead correspond to the dark and light green arrowheads in Fig. 2C, respectively. Another series of consecutive death/ engulfment/ death events occuring nearby in this movie is tracked by a blue/grey series of arrowheads in Fig. 2C. The z-stack used to produce the maximum projection shown here is somewhat thicker than in Fig. 2C, such that at the beginning, on the right side, it includes macrophages that are not within the brain but above it.