Figure 4

The dynamic expression of CABYR-A in mouse spermiogenesis. Immunofluorescent localization of mouse CABYR-A in paraffin sections of mouse testis were studied by using anti-CABYR-A polyclonal antibody (A-H) or pre-immune control (I), and Cy3-conjugated secondary antibodies. Column 1: Bright field phase images; Column 2: Corresponding indirect immunofluorescence; Column 3: Overlay of 1 and 2. No red fluorescence is observed in the spermatids in steps 9 and 10 (stage IX-X of the cycle) (A). Very faint red fluorescence representing CABYR-A protein is first visible in the cytoplasm of step 11-12 elongating spermatids (stage XI-XII) (B). CABYR protein becomes progressively more intense in the spermatid cytoplasm from step 13 (stage I) through step 15 (stage VI) (C-F). Staining is first noted in the sperm flagellum at step 15 (stage V-VI) (F) and appears in the principal piece of the flagellum at early step 16 (stage VII) accompanied by decreasing staining in the spermatid cytoplasm (G). Cytoplasmic staining of round spermatids was not evident and red fluorescence was found only in the principal piece of spermatid flagellum at late step 16 (stage VIII) (H). No immunofluorescence was observed with the pre-immune antiserum at any stage of spermatogenesis (I).