Expression of pUbq-Cnn-C^T results in major defects during male meiosis. (A and B) Phase-contrast images showing round spermatids from testes of flies expressing pUbq-Cnn-C (A) or pUbq-Cnn-C^T (B). Alterations in nucleus: nebenkern ratio (normally 1:1, asterisks in right panel) and size (normally approximately equal) indicate defects in cytokinesis and karyokinesis. (C) Graph showing quantification of the nucleus:nebenkern ratio (left panel: means and SDs indicated) and variance in nuclear diameter (right panel: geometric means and 95% CIs indicated, P value from an unpaired t test of log₁₀-tranformed data) in pUbq-Cnn-C (n = 22 cysts) and pUbq-Cnn-C^T (n = 27 cysts) testes. (D and E) Fluorescence images showing spermatocytes or round spermatids at different developmental stages, as indicated, from testes of flies expressing pUbq-Cnn-C (D) or pUbq-Cnn-C^T (E) stained for microtubules (green, α-tubulin), centrosomes (pink, asterless), and DNA (blue). Defects within cells expressing pUbq-Cnn-C^T include an apparent high density of cytosolic microtubules, abnormal spindles, and too many nuclei.