Fig. 5. XHes2 promotes extra Müller cell production by affecting both glial cell birthdate and retinal precursor proliferation. (A-M) Analysis of BrdU incorporation (3 hour pulse) in retinal clones, following GFP or GFP plus XHes2 lipofection. (A) Percentage of BrdU-positive cells among GFP-transfected retinal cells (76, 509, 707 and 544 cells for the control; 124, 347, 1058 and 322 for XHes2 at stages 30, 33/34, 35/36 and 37/38, respectively). (B-M) Typical sections of stage 33/34 (B-G) or 37/38 (H-M) retinas immunostained for both GFP and BrdU, following lipofection of GFP alone (B-D,H-J) or GFP plus XHes2 (E-G,K-M). At stage 37/38, BrdU-positive cells in the control are mostly restricted to the CMZ, while many XHes2-overexpressing cells are still proliferating in the central retina (compare arrows in I and L). (N-Q) Birthdating experiments. Embryos lipofected with either GFP alone or GFP plus XHes2 were injected with BrdU every 8 hours from stage 34 to stage 41. (N) Percentage of BrdU-positive cells among GFP-transfected Müller cells (22 Müller cells for the control and 41 for XHes2). (O-Q) An example of GFP and BrdU double staining following XHes2 overexpression. Arrows indicate GFP-positive Müller cells that are BrdU negative. Abbreviations: GCL, ganglion cell layer; INL, inner nuclear layer; LE, lens; ONL, outer nuclear layer. Values are given as mean±s.e.m. ^*P<0.05, ^***P<0.001 (Student's t-test).