Fig. 5

Mutant PLL primordia collapse is due to decreased proliferation and depletion of leading zone cells. (A-H) Cell proliferation analysis in wild-type (A-D) and lef1^u767 mutant (E-H) Tg(-8.0cldnb:lynEGFP)^zf106 embryos. After BrdU pulse and chase, embryos were fixed after deposition of neuromast L1 (A,E), L2 (B,F), L3 (C,G) and L4 (D,H). Brackets show the primordium. Scale bars: 20 μm. (I) BrdU-positive cells/total cell ratio in wild type (white bars) and lef1^u767 mutants (red bars) after one to four deposited neuromasts. Total cells where counted after DAPI staining nuclei. Significance was tested with Wilcoxon rank-sum test (^***P<0.001). Data are mean+s.d. (J,K) 48 hpf aphidicolin/hydroxyurea-treated Tg(cldnb:lynGFP)^zf106 embryos show three or four widely spaced neuromasts and a caudally extended row of cells (J). Red arrows indicate neuromasts. (K) Amplification of red rectangle in J. (L-O) Kaede photoconverted leading edge cells at 24 hpf in wild type (L) and lef1^u767 (N) assessed at 35 hpf (M,O). Brackets indicate preformed neuromasts. (P,Q) Ablation of the caudal third of PLLP at 24 hpf leads to a lef1^u767-like phenotype with 20%, 33.3% and 46.6% of the embryos displaying 3, 5 and 7 neuromasts respectively at 72 hpf (15 ablated specimens). Red arrows indicate neuromasts. (Q) Inset from P with red arrow showing the remaining migrating cells.