Figure 7.

Structural analysis of elongating spermatids by TEM. (A) Wild-type elongating spermatids show normal assembly of the manchette and chromatin condensation. The morphology of the head and acrosome develops normally as well. Elongating spermatids from knockout mice have several defects. The manchette structure is disorganized (green arrows) or absent. Chromatin condensation is affected (blue arrowhead) as well as the nucleus and acrosome shapes. The orange arrows show detached acrosomes; * shows dispersed outer dense fiber material. The pink arrows show disorganized mitochondria. (B) TEM microscopy from testis samples shows some axonemes missing one CP microtubule (9 + 1) indicated by the red arrow; however, the majority of the axonemes show the 9 + 2 arrangement of their microtubules. (C) Fibrous sheath and outer dense fibers were observed in the wild-type testis (the blue arrow points to a representative flagellum showing these structures). However, these structures were not observed around the axoneme in the knockout flagella. Red arrow indicate 9 + 1 axoneme. WT, wild-type; KO, knockout; ODF, outer dense fibers; FS, fibrous sheath.