Fig. 2: Spermatocytes in the SV of Sox17-cKO mice.
a Transmission electron microscopy (TEM) of Sertoli cells on the border of the RT. Sertoli cells located within the putative SV region in Sox17-cKO testes harbored spermatocytes (blue stars) packed into apical cell processes with adherence junction (yellow arrows) constructing ectoplasmic specialization (red arrows), which is not normally observed in SV Sertoli cells. In contrast, SV Sertoli cells in the control did not support spermatocytes, and their cytoplasm was enriched with microtubule bundles (blue asterisk), forming multiple large vacuoles facing the tubular lumen (red asterisk). b Whole-mount immunohistochemistry of SCP3 (spermatocyte marker) and GFRα1 (Aundiff marker) and schematic illustration of the SV fragments with their quantification (b′). Spermatocytes were observed up to the edge of the SV in Sox17-cKO mice, while the distribution pattern of Aundiff in the putative SV region did not significantly differ between the Sox17-cKO and control groups. SCP3: Control n = 3, Sox17-cKO n = 3, GFRα1: Control n = 6, Sox17-cKO n = 6. c GFRα1, SOX9, PLZF (Aundiff marker), cKIT (Adiff marker), and SCP3 immunostaining of three serial testis sections from 4-week-old Sox17-cKO mice and their littermate controls. SV epithelia in the control support Aundiff, whereas the putative SV epithelia in Sox17-cKO mice support spermatocytes together with Adiff. Lower panels in c represent magnified images of the region surrounded by broken rectangles in the upper panels. Data are mean ± s.e.m. Comparisons were made using a two-tailed unpaired Student’s t test (b′). *P < 0.05. Broken line, outlines of the ST; Aundiff: undifferentiated spermatogonia; Adiff: differentiating spermatogonia, RT: rete testis, SV: Sertoli valve. “n” represents the number of biological replicates. Scale bars, 2 μm (a), 50 μm (b, c).
