Figure 3: Expression of beta-cell markers in INS-GFP expressing cells at passage 3 after sorting. (a) Expression of INS-GFP. (b) Negative control stained with isotype control antibodies. (d, g, j) INS-GFP expressing cells that co-express (e) insulin, (h) proinsulin, and (k) PDX-1. (c, f, i, l) Merged images. Scale bar = 10 μm.