Fig. 1. Spermatogenesis defects in unc mutants. (A,B) Cysts of elongating spermatids in wild-type (A) and unc mutant (B) testis, stained for nuclei (red) and ß-tubulin (blue). Nuclei are clustered at the head of wild-type cysts but are dispersed in unc mutants. (C) Nuclei in cysts of an unc mutant testis, stained for DNA (red) and -tubulin (blue). Two stages of nuclear condensation are present. Earlier, less-condensed nuclei (left side of panel) are still associated with the -tubulin-containing centriole adjuncts as in wild type, but mutant nuclei (arrows) and adjuncts (arrowheads) frequently detach at later stages. Mutant nuclei do not condense further than the stage seen in cross-section on the right. (D-F) Ultrathin sections of wild-type (D) and mutant (E,F) testes. Wild-type spermatids have a canonical 9+2 axoneme, associated with an electron-dense mitochondrial derivative. Most mutant axonemes are partially or completely disrupted, and lose their tight association with mitochondrial derivatives. Scale bars: in A-C, 5 µm; in D,F, 0.2 µm.