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PAPC mediates self/non-self-distinction during Snail1-dependent tissue separation.

Luu O, Damm EW, Parent SE, Barua D, Smith TH, Wen JW, Lepage SE, Nagel M, Ibrahim-Gawel H, Huang Y, Bruce AE, Winklbauer R - J. Cell Biol. (2015)

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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada M5S 3G5.

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Ultrastructure of cleft contacts. Cells after 20 min of reaggregation. (A) Pair of mesoderm (large yolk platelets) and ectoderm cells (small platelets). (B) Alternating large gaps and narrow contacts between cells of ectoderm–mesoderm pair. (C and D) High-magnification views of regions of close (C) and intermediate contacts (D), respectively, of a cell pair. (E and F) Cleft contact ECM stained with lanthanum/alcian blue. ECM stretching across gaps (small arrows) or in patches on cell surface and in large gaps (dashed arrows) is shown. (G and H) Contacts between normal ectoderm and PAPC-MO–injected prechordal mesoderm cells, ECM stained with lanthanum/alcian blue. e, ectodermal BCR; m, prechordal mesoderm; l, large gaps; i, intermediate contacts; c, close, adherens junction–like contacts; sc, super-close contacts; large arrows, points of divergence of membranes at end of intermediate contacts.
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fig9: Ultrastructure of cleft contacts. Cells after 20 min of reaggregation. (A) Pair of mesoderm (large yolk platelets) and ectoderm cells (small platelets). (B) Alternating large gaps and narrow contacts between cells of ectoderm–mesoderm pair. (C and D) High-magnification views of regions of close (C) and intermediate contacts (D), respectively, of a cell pair. (E and F) Cleft contact ECM stained with lanthanum/alcian blue. ECM stretching across gaps (small arrows) or in patches on cell surface and in large gaps (dashed arrows) is shown. (G and H) Contacts between normal ectoderm and PAPC-MO–injected prechordal mesoderm cells, ECM stained with lanthanum/alcian blue. e, ectodermal BCR; m, prechordal mesoderm; l, large gaps; i, intermediate contacts; c, close, adherens junction–like contacts; sc, super-close contacts; large arrows, points of divergence of membranes at end of intermediate contacts.

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).


PAPC mediates self/non-self-distinction during Snail1-dependent tissue separation.

Luu O, Damm EW, Parent SE, Barua D, Smith TH, Wen JW, Lepage SE, Nagel M, Ibrahim-Gawel H, Huang Y, Bruce AE, Winklbauer R - J. Cell Biol. (2015)

Ultrastructure of cleft contacts. Cells after 20 min of reaggregation. (A) Pair of mesoderm (large yolk platelets) and ectoderm cells (small platelets). (B) Alternating large gaps and narrow contacts between cells of ectoderm–mesoderm pair. (C and D) High-magnification views of regions of close (C) and intermediate contacts (D), respectively, of a cell pair. (E and F) Cleft contact ECM stained with lanthanum/alcian blue. ECM stretching across gaps (small arrows) or in patches on cell surface and in large gaps (dashed arrows) is shown. (G and H) Contacts between normal ectoderm and PAPC-MO–injected prechordal mesoderm cells, ECM stained with lanthanum/alcian blue. e, ectodermal BCR; m, prechordal mesoderm; l, large gaps; i, intermediate contacts; c, close, adherens junction–like contacts; sc, super-close contacts; large arrows, points of divergence of membranes at end of intermediate contacts.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4362454&req=5

fig9: Ultrastructure of cleft contacts. Cells after 20 min of reaggregation. (A) Pair of mesoderm (large yolk platelets) and ectoderm cells (small platelets). (B) Alternating large gaps and narrow contacts between cells of ectoderm–mesoderm pair. (C and D) High-magnification views of regions of close (C) and intermediate contacts (D), respectively, of a cell pair. (E and F) Cleft contact ECM stained with lanthanum/alcian blue. ECM stretching across gaps (small arrows) or in patches on cell surface and in large gaps (dashed arrows) is shown. (G and H) Contacts between normal ectoderm and PAPC-MO–injected prechordal mesoderm cells, ECM stained with lanthanum/alcian blue. e, ectodermal BCR; m, prechordal mesoderm; l, large gaps; i, intermediate contacts; c, close, adherens junction–like contacts; sc, super-close contacts; large arrows, points of divergence of membranes at end of intermediate contacts.
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).

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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada M5S 3G5.

Show MeSH
Related in: MedlinePlus