Fig. 6 Transgenic Ras activation induces Fgf target genes in fin regenerates. (A) Whole-mount ISH and representative sections of epidermal gene expression 5 h after a single heat-shock in 4 dpa wildtype and hsp70:v-ras regenerates. Brief Ras activation increases and expands pea3 and erm expression in the basal epidermal layer, as well as the other Fgf target genes mkp3 and spry4 (arrowheads). (B) Images of whole-mount ISH and representative sections of 4 dpa regenerates from hsp70:dn-fgfr1, wildtype, hsp70:v-ras, and hsp70:dn-fgfr1; hsp70:v-ras animals, collected 5 h after a 38 °C heat-shock. While Fgfr inhibition depletes pea3 expression from the basal epidermal layer (far left), Ras activation expands pea3 expression proximally (third from left). Double-transgenic hsp70:dn-fgfr1; hsp70:v-ras regenerates (far right) display similar ectopic induction of pea3 expression as hsp70:v-ras single transgenics.
Reprinted from Developmental Biology, 331(2), Lee, Y., Hami, D., De Val, S., Kagermeier-Schenk, B., Wills, A.A., Black, B.L., Weidinger, G., and Poss, K.D., Maintenance of blastemal proliferation by functionally diverse epidermis in regenerating zebrafish fins, 270-280, Copyright (2009) with permission from Elsevier. Full text @ Dev. Biol.