Fig. 8 . PAR1 synergizes with XDelta-1 to induce ciliated cell differentiation and inhibits the Notch target ESR6e. Four- to eight-cell embryos were unilaterally injected with the indicated RNAs and lacZ RNA as a lineage tracer (light blue staining) and subjected to in situ hybridization with the ESR6e (A,B) or -tubulin (E-L) probes. (A,B) Superficial staining for ESR6e is unaffected in cross-sections of lacZ RNA-injected control embryos (A, 100 pg), but is inhibited in PAR1 RNA-injected embryos (B, right side, arrowhead, 250 pg). (C) Basolateral localization of XDelta-1 in Xenopus ectoderm. (D) XDelta-1 is detected in multiple cytoplasmic vesicles (arrowheads) in the presence of PAR1. (E) Uninjected embryo. (F,G) XDelta-1 RNA alone (F) or low dose of PAR1 RNA (G) do not significantly alter the number of ciliated cells. (H) The synergistic effect of coinjected PAR1 and XDelta-1 RNAs on ciliated cell development. (I,J) PAR1 does not influence the activity of a dominant intracellular inhibitor of the Notch pathway, dnRBP/j, which can stimulate ciliated cell development. (K) Notch-ICD suppresses ciliated cell differentiation. (L) PAR1 does not alter Notch-ICD activity. (M-O) Quantification of the effects shown in E-J, presented as numbers of ciliated cells per section (M,N) and frequency of embryos with increased -tubulin staining (O). Numbers of examined embryos are shown above bars. The data are representative of three independent experiments.