Figure 11

Testicular ultrastructure of WT and Dcaf17^−/− adult mice by transmission electron microscopy (TEM). Representative TEM images of 8 weeks old WT (A–F) and Dcaf17^−/− (G–R) mice testes ultrathin sections displaying different steps of spermiogenesis. Spermatids in step 3–5 (A,G,M), step 6–7 (B,H,N), step 8–9 (C,I,O), step 10 (D,J,P), step 11–12 (E,K,Q) and step 15–16 (F,L,R) are represented. In WT (A) and Dcaf17^−/− (G,M) testes, round spermatids during steps 3–5(A,G,M) show acrosome (Ac) attached with spherical nucleus (Nu) at one end. Some round spermatids show Golgi (Go) apparatus located close to acrosome (Ac). During steps 6 and 7 of spermiogenesis in WT (B) and Dcaf17^−/− (H,N) testes, the acrosome (Ac) flattens and grows to form a cap covering approximately half of the nuclear (Nu) surface. During steps 8–12 of WT spermiogenesis, the spermatid nucleus (Nu) starts to elongate and the acrosome (Ac) extends along the nuclear envelope (C,D,E). The manchette (Mn) in WT elongating spermatids (C,D,E) extends from perinuclear ring (PR) into residual body (RB) and attached to posterior region of nuclear membrane. The Dcaf17^−/− elongating spermatids in steps 8–12 (I–K and O–Q) show abnormal nuclear elongation and asymmetric extension of the acrosome (Ac) that is associated with distorted nucleus (Nu). The perinuclear ring (PR) in the elongated spermatids of Dcaf17^−/− mutant (I–K and O–Q) is abnormally positioned and microtubule bundles of manchette (Mn) are severely disorganized along the posterior surface of the deformed nucleus (Nu). WT elongated spermatids in steps 15–16 show elongated nucleus (Nu), a midpiece (MP) region containing uniformly distributed mitochondria (Mt) and connecting piece (CP) joining the midpiece region of the tail to the head of maturing spermatozoa. The manchette (Mn) and residual body (RB) gradually disappear during the maturation steps 15–16 in WT. Elongated spermatids at steps 15–16 in Dcaf17^−/− testis (L,R) show oval shaped nucleus (Nu), abnormal manchette (Mn) (L) and residual body (RB). Scale bars: (A–E), (G–K) and (M–R) 5 µm; F and L 2 µm.