Developmental regulation of BLBP-positive radial glia and BrdU-positive proliferative cells in the <i>Xenopus</i> tectum.

<p>(A). A cartoon showing the tectum at stage 47. The right lobe of the brain was transfected with CMV::eGFP using method of unilateral brain electroporation. The eGFP-expressing cells within the tectum show a characteristic radial glial cell morphology with triangular cell bodies (arrow head), long processes (asterisk) and large end feet (arrow). Scale: 50 μm. (B). The majority of eGFP-expressing cells in the optic tectum are also BLBP-positive. Right panel: a higher magnification image of the right tectum, Scale: 50 μm. (C-D). <i>Xenopus laevis</i> were incubated with BrdU for 2 hours and co-labeled with anti-BrdU and anti-BLBP antibodies at stage 46 (C) and stage 49 (D), respectively. Six representative sections were shown for stage 46 (C1-C6: BrdU staining; C7-C12: BLBP staining and C13-C18: BrdU and BLBP merged) and stage 49 (D1-D6: BrdU staining; D7-D12: BLBP staining and D13-D18: BrdU and BLBP merged), respectively. Arrows indicate the end feet of RGs. Data represent the average cumulative cell counts for 8 sections per brain (Note: remaining figures show one representative section per condition). The shape of the tectal brain was outlined with a dotted line. The counting area was outlined with a white square (C4 and C10). (E). The zoom in images from the square area (C4, C10 and C16) was shown. Arrows indicate cells co-labeled with BrdU (green) and BLBP (red). Scale: 100 μm. (F-G). Quantification of BrdU- and BLBP-positive cells in whole-mount tecta showed decreases in the numbers of BrdU- and BLBP-labeling cells at stage 49 compared to stage 46 (BrdU: St 46, 288.3 ± 24.7, N = 3, St 49, 78.0 ± 7.4, N = 5; BLBP: St 46, 371.3 ± 28.4, N = 3, St 49, 105.2 ± 8.2, N = 5; ***p<0.001). (H). The majority of BrdU-labeling cells are colocalized to BLBP-positive cells at stage 46 and 49 (St 46: 80.6% ± 3.5%, N = 3, St 49: 80% ± 2.3%, N = 5, p = 0.72).