Fig. 5.

Integrin signaling is required for proper localization of neoblasts and progenitor cells in regeneration. (A) Regenerating tail fragments fixed after 15 days of regeneration and stained for smedwi-1 expression marking neoblasts. Neoblasts (arrows) could be identified in greater abundance in the ventral anterior brain region of β1-integrin(RNAi) animals versus control animals. (B) Neoblasts were present in the head tip region anterior to the brain of 15-day regenerated tail fragments, normally devoid of these cells. Right: quantification of smedwi-1⁺ cell numbers. (C-E) Brain progenitors (C, pax6A⁺smedwi-1⁺; D, coe⁺smedwi-1⁺) and eye progenitors (E, ovo⁺smedwi-1⁺) were detected by double FISH in the head region of day 15 regenerating tail fragments imaged dorsally or ventrally at 10× (upper) or 40× (lower). Quantification is shown below of average numbers of progenitor cell numbers from stacks of 60-70 µm-thick ventromedial regions imaged at 40× with 1-µm slices. Arrows indicate representative double-positive cells. β1-integrin RNAi caused mislocalization of pax6A⁺ and ovo⁺ progenitor cells and increased their numbers. Error bars represent s.d.; **P<0.01, ***P<0.001 by two-tailed t-test. Scale bars: 150 µm.