PAPC mediates self/non-self-distinction during Snail1-dependent tissue separation.
Bottom Line: First, PAPC attenuates planar cell polarity signaling at the ectoderm-mesoderm boundary to lower cell adhesion and facilitate cleft formation.It consists of short stretches of adherens junction-like contacts inserted between intermediate-sized contacts and large intercellular gaps.These roles of PAPC constitute a self/non-self-recognition mechanism that determines the site of boundary formation at the interface between PAPC-expressing and -nonexpressing cells.
Affiliation: Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada M5S 3G5.Show MeSH
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Mentions: Between ectoderm–mesoderm cell pairs reaggregated in vitro for 20 min (Fig. 9 A), a similar pattern of contacts was observed. Large gaps were interspersed with intermediate and close adherens junction–like contacts (Fig. 9, B–D). Regularly spaced membranes of intermediate contacts diverged abruptly at the surface of cell pairs or at large gaps (Fig. 9 D), again suggesting an adhesive role for these structures. Patches of ECM decorated free cell surfaces and spanned between membranes up to 0.5 µm apart at contacts (Fig. 9, E and F). Knockdown of PAPC generated long stretches of super-close contacts with separation distances of 10 nm (Fig. 9, G and H). In occasional gaps, dense material resembling compacted ECM was present (Fig. 9 H). In PAPC morphant embryos, the fraction of close contacts at Brachet’s cleft increased to 48 ± 4.2% (n = 4 embryos).
Affiliation: Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada M5S 3G5.