Fig 1. Abundance of cell contacts but not relative adhesiveness is reduced in adhesion factor morphants.

(A–C) Dorsal side of normal (A) and C-cad depleted stage 11 gastrulae (B). In Syn-4 depleted embryos (C) convergent extension appears slightly accelerated in 6 out of 7 gastrulae. CM, chordamesoderm; NE, neural ectoderm; PCM, prechordal mesoderm; EN, suprablastoporal endodermal epithelium; red arrow, tip of archenteron; red arrowhead, position of blastopore. (D–H’) Cell packing in normal (wt) and morphant (MO) stage 11 chordamesoderm. Blue arrowheads, narrow contacts between cells; green arrows, two-sided gaps (“bubbles”) between two cells; light green arrowheads, wide contacts between cells; g, gaps at 3- or 4-cell junctions. (I) Abundances of narrow (< 50 nm) and wide (> 50 nm) contacts, and interstitial gaps. Bars, standard deviations. (wt) is from Barua et al. [4]. n, number of TEM images analyzed. (J) Tensions at 3-sided gap. For tension β_f at free gap surface to balance tension per cell β_c at contact interface it must act at a contact angle θ. (J’) Same contact angle θ and thus relative adhesiveness α can combine with large (left) or small (middle) contacts (small or large gaps, respectively). Same θ can be generated by smaller (${\beta }_f^{\prime }$ and ${\beta }_c^{\prime }$) or larger (${\beta }_f^{″}$ and ${\beta }_c^{″}$) tensions, provided that their ratio is retained. (K) Each dot represents a measured angle 2θ in normal and morphant CM; av., average.