(L-O) Lateral images of the FLS (L, N; dotted line) or dorsolateral CCV region from where the FLS normally sprouts (M, O; dotted line) fixed at 36 hpf in lyve1b:EGFP embryos that have been fluorescently immunostained with anti-PROX1 (green) and anti-GFP (red). These show no change in the number of Prox1-positive lymphatic progenitors in the ccbe1 morpholino-injected (M) and sFLT4 mRNA-injected (O) embryos compared with control morpholino-injected (L) and uninjected (N) embryos. (P) Quantitation of the percentage of dorsolateral CCV ECs that are lymphatic progenitors relative to the total number of dorsolateral CCV ECs in control morpholino-injected (n = 26), ccbe1 morpholino-injected (n = 27), uninjected (n = 28) and sFLT4 mRNA-injected embryos (n = 32). (Q) Quantitation of the total number of dorsolateral region CCV ECs in 36 hpf embryos that were uninjected or injected with control morpholino (n = 26), ccbe1 morpholino (n = 27), or sFLT4 mRNA (n = 32). 