PAPC in tissue separation. (A and B) Quantitation of separation behavior; Xenopus (A) and zebrafish (B) mesoderm test explants on BCR/epiblast. (C and D) RT-PCR of variously injected Xenopus BCR at stage 10 to detect Xsnail1 or PAPC mRNA. TB WE, tailbud stage whole embryo. (E) Ectopic separation behavior in Xenopus BCR. Variously injected BCR test explants were placed on uninjected BCR. (F) Inferred control pathway. (G–L) Ectopic cleft formation in Xenopus BCR. One side of prospective BCR was injected with RDA, cleft was observed in incident light (arrowheads, top), and cell sorting in red fluorescence (bottom). n, number of explants. (M) Quantitation of separation behavior. (left) Xenopus mesoderm on PAPC-injected BCR; (right) M-PAPC BCR on uninjected or M-PAPC BCR. (N) Tissue surface tension of uninjected BCR or BCR expressing DN C-cadherin or M-PAPC. n, number of cell aggregates. Standard deviations are indicated.