Figure 2 - figure supplement 1

Analysis of proliferation in the OF margin.

(a) Schema for quantifying Phospho-Histone H3A foci within confocal Z-stacks taken of whole mounted fissures using a region of interest grid system. (b) Representative image showing positive nuclei (red). ROI grids used were 200 × 200 μm; all positive foci were recorded. P-D axis is shown for (a) and (b). (c) Quantified Phospho-Histone H3A immunostaining of whole-mounted fissures. Fewer proliferating cells (p=0.1093) were observed at HH.St29 within the seam (mean = 66.0, SD = 20.30) compared to outside the seam (mean = 90.8, SD = 32.6), and at HH.St30 (p=0.0063; mean fused seam = 86.8, SD = 32.3; within seam mean = 60.2, SD = 21.8); Student’s t-test used to compare within and outside seam. Data shown are the mean of three fissures per stage with standard deviations indicated. Note: Central seam length was too small to quantify in HH.St29 fissures (<200 μm), however phospho-Histone H3A foci were fewer at the fusion points compared to non-seam regions. (d) Representative phospho-Histone H3A immunostaining of serially-sectioned fissures at HH.St29 revealed the presence of mitotic cells within the apical neural retina throughout the ventral eye. Phospho-Histone H3A was not enriched in the fused seam (HH.St30; n = 3).