Figure 2. Timelaspe imaging reveals a pause in snVII growth accompanied by transient axonal extension and retraction in control, but not in glo^m117 embryos as snVII turns from a dorsal to a caudal vector.

Row A shows frames from a tg(p2xr3.2:eGFP^sl1) control timelapse movie. In control embryos, elongation of snVII pauses between 50h and 60h. Arrows in row A indicate the axon fascicles that are extended and retracted before snVII turns to grow caudally and meet snIX and snX at the hindbrain plexus. Row B shows frames from a timelapse movie of a tg(p2xr3.2:eGFP^sl1);glo ^m117 mutant embryo. In the mutant, snVII continues growing in the dorsal direction and the transient axon extensions and retractions are absent. Age of embryos is shown in upper left corner of each image. In all images rostral is to the left, dorsal to the top.