Fig. 1

Calcium transients are enriched in the MHB at 18 ss and precede decreases in cell length. (A) Representative wild-type 18 ss time-lapse images of intracellular Ca²⁺ transients (panels from Supplemental Movie S1). Asterisks indicate mitotic cells, and arrows indicate Ca²⁺ transients analyzed. (B) Quantification of Ca²⁺ transients at 18, 20, and 24 ss. (C–E) Representative wild-type images at 18 ss analyzed for cell length changes after Ca²⁺ transients. (F) Quantification indicating the amount of decrease in cell length immediately after Ca²⁺ transients. For statistical analysis, one-way ANOVA with Tukey’s HSD post hoc test was conducted for Ca²⁺ transient frequency. *p < 0.05, mean ± SEM. Embryos analyzed: 18 ss, n = 11; 20 ss, n = 10; 24 ss, n = 8. Mann–Whitney U test was performed for analysis of cell length decrease after Ca²⁺ transients. ***p < 0.001, mean ± SEM. Embryos analyzed, n = 10; MHB region cells, 17; outside MHB cells, 6. Arrowheads indicate the MHBC. Scale bars, 25 μm.