FIG. 1.

Altered ultrastructure of tight junctions in S-Ar mutant testes. Electron micrographs of WT and S-Ar mutant seminiferous epithelium. A) WT seminiferous tubule. Boxed region contains a tight junction formed between the two adjacent Sertoli cells. B) Higher magnification of the boxed region in A. Arrows indicate regions of close apposition of Sertoli cell lipid bilayers (kissing points). C) Seminiferous tubule of an S-Ar mutant. Boxed region shows the intercellular space of two neighboring Sertoli cells. D) High magnification of the boxed region in C. Note the absence of kissing points between the membranes of the adjacent Sertoli cells (arrow heads). SC, Sertoli cells. Bar in A = 2 μm for A and C; bar in B = 200 nm for B and D.