Fig. 3. PAR1 promotes ciliated cell differentiation. Four- to eight-cell embryos were unilaterally injected with lacZ RNA (light blue staining) or PAR1 RNAs or MO as indicated and subjected to in situ hybridization for -tubulin expression at stages 13-14. (A-D) T560A increases the number of -tubulin-expressing cells in epidermal ectoderm. (C,D) Cross-sections of embryos shown in A,B. A single layer of -tubulin-positive cells in control ectoderm (C) expanded to a double layer of positive cells in T560A-expressing ectoderm (D, arrowhead). (E,F) Enhanced cilia differentiation in T560A RNA-injected embryos at stage 18 (F), when compared with uninjected controls (E), revealed by immunostaining for acetylated tubulin. Arrowhead in E demarcates ciliated cells that migrated to the surface. Arrow in F indicates ectopic ciliated cells remaining in the inner ectoderm layer. (G,H) PAR1B MO decreases the number of -tubulin-expressing cells (H) as compared with the uninjected side (G). (I) Uninjected embryo; (J) PAR1 RNA increases ciliated cell number (white arrow); (K) PAR1 KD RNA has no significant effect on ciliated cells. Lateral view is shown in all panels, except I-K (ventral view).