Fig. 6. A morphological boundary was induced to form at an interface between host and Lfng/Notch-electroporated donor tissues. (A) A diagram showing a manipulation to create a sharp border of Lfng activity. Lfng or Notch E DNA was electroporated into PSM of a donor embryo together with GFP, and subsequently a small piece was dissected from a donor PSM, and transplanted into a host. (B) An ectopic fissure was formed at the boundary between the donor (GFP-positive cells in the right panel; arrowhead) and host regions. (C) A confrontation between NotchE-positive and -negative cells gave a similar result to that in B, whereas Notch LNG did not show such effects (D). The left and right panels in B-D show the same specimen with the position of a fissure and electroporated donor-derived cells (green), respectively, indicated. (E) A sagittal section of the supernumerary somites resulting from a Lfng boundary. Anterior is at left. Epithelial cells visualized by phallodin stainin (red) were present anterior to the Lfng-producing cells (green), whereas control GFP-expressing cells did not affect the epithelialization (F). The diagrams on the right of E and F show the position of the boundaries more clearly.