Biphasic Zac1 expression in the retina. Zac1 (a-e) transcript and protein (f-j) distribution from E10.5 to P7. Arrowheads in (d,g,i) mark limits of higher expression domains. (k-o) Identification of Zac1+ P7 retinal cells. Co-labeling with Zac1 (red) and CRALBP (green (k,k')), calbindin (green (l,l')), Pax6 (green (m,m')), PKC (green (n,n')) and Brn3a (green (o,o')). High magnification images of boxed areas are shown in (k'-o'). Arrowheads mark double+ cells. Of 2,154 Zac1+ cells analyzed, 1,238 CRALBP/Zac1 double+ Müller glia; 29 calbindin/Zac1 double+ horizontal cells (based also on morphology), 480 Pax6/Zac1 double+ amacrine cells (in the INL) and 407 Brn3a/Zac1 double+ RGCs were identified. GCL, ganglion cell layer; inbl, inner neuroblast layer; INL, inner nuclear layer; le, lens; lv, lens vesicle; onbl, outer neuroblast layer; ONL, outer nuclear layer; ov, optic vesicle.