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: PAPC is proposed to act synergistically with Xfz7 during tissue separation (Medina et al., 2004). PAPC-MO indeed reduced separation behavior, but morphants could not be rescued by CA-JNK or Xsnail1 mRNA (Fig. 3 A), and PAPC-MO did not diminish Xsnail1 expression (Fig. 2, B and C). Moreover, PAPC coexpression was not essential for induction of Xsnail1 expression in the BCR by Xfz7b (Fig. 3 C). Thus, PAPC does not act on Xsnail1 expression through the Xfz7/JNK/Jun pathway. Conversely, PAPC expression was not induced by Xsnail1 mRNA in the BCR (Fig. 3 D), indicating that Xsnail1 and PAPC are regulated independently and that both factors are required for tissue separation. In the zebrafish, knockdown of the PAPC homologue pcdh8 also inhibited separation behavior, and separation could be rescued by pcdh8 mRNA (Fig. 3 B).
Affiliation: Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada M5S 3G5.