Fig. 4

Delay in cell shape changes of marginal EVL cells. (A–F) Confocal z-projections of Alexa488-Phalloidin stained embryos showing a delay in flattening of marginal EVL cells. (A, C, E) WT; (B, D, F) MZspg^m793 embryos. (A, B) 50% epiboly; (C, D) 75% epiboly; (E, F) 90% epiboly. All MZspg^m793 stages are time-matched to wild-type embryos. yc: yolk cell. Scale bar: 100 μm. (G) Measurements of the average border cell length of 10–15 marginal EVL cells including SE. 30% epiboly: WT = 100 ± 8%; MZspg^m793 = 103 ± 6% (p = 0.205). 50% epiboly: WT = 100 ± 5%; MZspg^m793 = 115 ± 4% (p = 0.029). Shield stage: WT = 100 ± 4%; MZspg^m793 = 124 ± 7% (p = 0.011). 75% epiboly: WT = 100 ± 2%; MZspg^m793 = 246 ± 2% (p = 0.069). 90% epiboly: WT = 100 ± 12%; MZspg^m793 = 117 ± 5 (p = 0.122). Data were normalized on WT results set as 100%. Asterisks highlight significant differences. (H) Measurements of the length to width ratio of marginal EVL cells. For each stage the length to width ratio of 10 adjacent cells was determined in 10 embryos of each wild-type or MZspg^m793. The graph represents average data from 100 cells for each genotype and stage, bars indicate standard deviation. 50% epiboly: MZspg^m793 = 1.24 ± 0.42; WT = 1.26 &p00 cells for each genotype and stage, bars indicate standard deviation. 50% epiboly: MZspgp = 0.8004; paired Student′s t-Test); 75% epiboly: MZspg^m793: 1.34 ± 0.53; WT = 1.63 ± 0.90 (p = 0.2349); 90% epiboly: MZspg^m793 = 1.81 ± 0.72; WT = 2.93 ± 1.25 (p