Fig. 2.

Cross-section electron micrographs through preindividualized (A and B) and mature (C and D) portions of spermatogenic cysts from wild-type (A and C) and TAZ deletion mutant (B and D) testes. Preindividualized spermatogenic cysts are similar in TAZ−/− (B) and wild-type (A) testes. These cysts are identifiable by their light-staining major mitochondrial derivatives (big arrow), in which an electron-dense material accumulates, enlarged minor mitochondrial derivatives (small arrow), and the presence of extensive cytoplasm between the axonemes (arrow head). After individualization, wild-type cysts contain highly ordered arrays of elongated spermatids that have undergone a significant reduction in the amount of cytoplasm that can be seen between the sperm tails (C). TAZ mutant cysts fail to undergo proper individualization and in them spermatid arrangements are grossly disorganized (D). (Scale bar, 1 μm.)