Fig. 8

Overexpression of gain- and loss-of-function yap transgenes alters RPE and NR cell fate. (A-D′) Images showing that overexpression of wild-type Yap (B,B′), constitutively active Yap (Yap S87A) (C,C′) and Taz (D,D′) induces ectopic pigmentation and retinal disorganization at 5dpf, as compared with the control (A,A′). Arrows indicate the presence of ectopic pigment cells. (E-G) Mosaic overexpression of dominant-negative forms of Yap (F) and Taz (G) results in ectopic loss of RPE cells at 48hpf, as compared with the control (E). Arrows indicate areas devoid of RPE cells. (H) Model of zebrafish RPE development. Bipotent progenitor cells assume either an RPE or NR fate based on Yap/Taz activity. In the absence of yap (right hemisphere of the eye cup), progenitors contributing to the central retina cannot form RPE. Those progenitors that contribute to the peripheral eye cup can upregulate Taz during their more lengthy migration and therefore form RPE.