Figure 3. OTX2ECR2 reporter expression in CTRL and OTX2^CRISPR retinas.

Retinas electroporated at E5 with OTX2ECR2::GFP and control or OTX2^CRISPR plasmids and analyzed after 48 hr. (A) Schematic representation of the chick OTX2 genomic locus, and the location of the ECR2 element, 1.5 kb upstream of the start codon. (B–D) OTX2ECR2::GFP reporter predominantly labels cells in the outer CTRL retina (B). This population is markedly reduced in both OTX2^CRISPR mutants (g2 in (C) and g3 in (D), and a new population located in the inner retina is formed. High magnification views of the regions boxed in the OTX2/GFP panels are shown in the rightmost panels. (E) Representative dot plots showing the overlap between OTX2ECR2::GFP (x-axis) and OTX2 protein (y-axis). The population of OTX2ECR2::GFP-positive cells that express OTX2 protein decreases in OTX2^CRISPR g2 retinas. (F) Quantification of the OTX2+/GFP+ cells from the total GFP+ cells for OTX2^CRISPR g2 (F) and g3 (G) compared to the controls. Error bars represent 95% confident intervals. *** represents p<0.0001, n ≥ 4 for both comparisons and each point represent one biological replicate. OR, outer retina; IR, inner retina.