Ultrastructural analysis of Drc7^-/- testis.

(A) and (B) Step 8 spermatids. No difference was observed between control and KO spermatids. Scale bar, 1 μm. (C) and (D) Step 10–11 spermatids. Both control and KO spermatids show a normal manchette structure (shown as “M”). Basal body (black arrowheads) were localized to the posterior region of the nucleus in both control and KO spermatids. Enlarged pictures are shown in (C’) and (D’). Scale bar in (C) is 2 μm and scale bars in (C’), (D), and (D’) are 1 μm. (E)—(H) Cross section of the midpiece of step 16 spermatids. Spermatids from Drc7^+/- mice show normal arrangement of mitochondria, outer dense fibers, and microtubules (E). In Drc7 KO spermatids, ‘9+2’ arrangement of microtubules was absent (F) or disorganized (G) and (H). White arrowheads indicate microtubule-like structures. Scale bar, 200 nm.