Figure 2: Basal cells undergo both symmetrical and asymmetrical divisions.

(a) Immunodetection of spindle orientation of a dividing basal cell in metaphase by staining for CK5 and γ-tubulin to indicate either horizontal or vertical divisions. Yellow arrowheads point to the positions of centrosomes indicated by γ-tubulin staining. (b) Quantification of the ratios of horizontal or vertical divisions over the total cell divisions in basal cells during development of anterior prostates. See Supplementary Table S1 for further data. (c) Quantification of the ratios of horizontal or vertical divisions over the total cell divisions in basal cells in different prostate lobes in P15 mice. See Supplementary Table S2 for further data. (d) Confocal analysis of cell fate specification in vertical division of basal cells by triple staining for Survivin, p63 and CK8. Yellow arrowheads point to the apical progeny that is p63 negative and CK8 positive, while red arrowheads point to the basal progeny that is p63 positive and CK8 negative. (e) Confocal analysis of cell fate specification in horizontal division of basal cells by triple staining for Survivin, p63 and CK8. Yellow arrowheads point to two daughter cells that are both p63 positive and express low CK8. (f) Immunodetection of asymmetrical division of basal cell by triple staining Survivin, p63 and Epcam. Yellow arrowheads point to the apical progeny that is p63 negative, while red arrowheads point to the basal progeny that is p63 positive. Dashed lines in a, d, e, f denote the positions of the basement membrane (bold) and the boundary of the dividing basal cells (light). All sections are counterstained by 4',6-diamidino-2-phenylindole (DAPI) (blue). Scale bars, 10 μm for each of the related panels.