Fig. 6. Mosaic expression of Lmo7 causes apical constriction.

a Scheme of the experiment. GFP-ZO1 RNA (100 pg) and Flag-Lmo7 RNA (100 pg) were coinjected into one ventral blastomere of 16-cell stage embryos. Adapted from Xenopus illustrations © Natalya Zahn (2022), Xenbase (www.xenbase.org RRID:SCR_003280)⁷⁵. b–g’ Representative images of GFP-ZO1 cells co-expressing Flag-Lmo7 in “sheet” (b, c’) or in “isolated” from Movies 4 and 5. Time-lapse imaging was initiated at stage 11. AC and AE cells are marked by red and blue, respectively. Asterisks show cells undergoing mitosis during the imaging. Rectangular areas in (b, b’ and d), d’ are enlarged in (c, c’) and (e–g’), respectively. Scale bars are 30 μm in (b, d) and 10 μm in (c, e–g). Experiments are repeated 3–5 times. Apical domain dynamics in the “sheet” (h) and “isolated” ectoderm (i). Each line represents apical domain size changes of an individual cell over 1.5–2 h. AC, AE, and “no change” cells (see Fig. 5 legend) are shown in red, blue, and green, respectively. Quantification was based on n = 66 cells from one Flag-Lmo7 (sheet) embryo and n = 20 cells from three Flag-Lmo7 (isolated) embryos. j Frequency (%) of AC, AE and “no change” cells in (h and i). These experiments were repeated 3–5 times. The Freeman–Halton extension of Fisher’s exact test. Two-sided. p = 0.00242.