Fig. 1: Deformation of the SV in Sox17-cKO mice.

a Schematic illustration of the RT, SV, and ST. b SOX17, SOX9 (Sertoli cell & RT marker), and CDH1 (RT marker) immunostaining of two serial sections showing the RT-SV junction at 4 weeks of age. c H&E staining showing disrupted geometry of the SV, with an increase in the valve leaflet angle seen in 4-week-old Sox17-cKO mice (c′). Control n = 6. Sox17-cKO n = 4. d SOX9 and CDH1 immunostaining showing reduced Sertoli cell density in the putative SV region in Sox17-cKO testis (d′). Control n = 3. Sox17-cKO n = 3. e SV-specific signals of acetylated tubulin (ace-TUB) and phosphorylated AKT (p-AKT) immunoreactivity were decreased in Sox17-cKO mice compared to the controls. f Schematic illustration of the injection of dye only into the RT, and surface views of the RT (left) and isolated SV fragments from the testis of which RT was injected with dye (right). The number of labeled STs per testis (i.e., the incidence of fluid backflow from the RT to the ST beyond the SV) increased significantly in Sox17-cKO compared to the controls (f′). Control n = 13. Sox17-cKO n = 11. Insets show magnified images of the region surrounded by broken rectangles (c, d). Data are mean ± s.e.m. Comparisons were made using a two-tailed unpaired Student’s t test (c', d', f'). *P < 0.05. Arrowhead, RT border; broken line, tubular wall; RT, rete testis, SV, Sertoli valve, ST, convoluted seminiferous tubule. “n” represents the number of biological replicates. Scale bars, 50 μm.