Gβγ signaling regulates the motility and polarity of PGC migration. (A-G) Epifluorescence time-lapse experiments performed on Tol-kop-EGFP-F-nos1-3′UTR embryos, with PGCs expressing membrane-bound GFP (memGFP) at low magnification (5× objective) at 8-10 hpf (supplementary material Movie 1). (A-C) Snapshots from time-lapse movies. Dorsal view; red dotted line indicates the notochord. (D-F) Representative tracks delineate PGC migration routes. (G) Average migration speed of PGCs. *P<0.01 versus control. Data are mean+s.e.m. (H-L) Confocal time-lapse imaging of PGCs expressing memGFP, taken at 8-10 hpf (supplementary material Movie 2). (H-K) Snapshots from movies of the control PGCs during the run phase (H) (green arrows indicate protrusion at the leading edge); Gαt- or Gγ2C68S-expressing PGCs (I,J) (red arrows indicate bleb-like protrusions); PGCs expressing Gγ2C68S in embryos treated with blebbistatin (K). Scale bars: 200 μm in A-C; 10 μm in H-K. (L) Orientation of blebs relative to the direction of PGC migration, as analyzed from four independent movies per group (10-second intervals, blebs grouped into 15° sectors).
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