Fig. 2. Expression of INCENP in spermatogonial mitosis (INCENP, green; ACA serum, red; DAPI, blue). (A,B) Partial projection of two focal planes throughout a spermatogonial interphase showing bright INCENP signals at heterochromatic chromocentres (arrows) highlighted with DAPI. ACA signals are located inside chromocentres. (C-E) Partial projection of three focal planes throughout a spermatogonial prophase. Bright fuzzy INCENP signals are located at centromeres (arrow in C,E) where pairs of ACA dots, representing sister kinetochores (arrows in D), are found. Inserts show a larger magnification of the arrowed centromere. A faint INCENP labelling is also found on condensing chromosomes. (F,G) Partial projection of five focal planes throughout an end-on view of a spermatogonial metaphase. A faint INCENP labelling is found on chromosome arms, whereas bright fuzzy signals are found at centromeric regions. The insert shows a centromeric region with its two sister kinetochores. (H,I) Partial projection of two focal planes throughout a spermatogonial anaphase. INCENP only labels some thin threads (arrows) at the spindle midzone. (J,K) Partial projection of two focal planes throughout a spermatogonial telophase where INCENP is present at two small and very bright signals (arrowheads) at both sides of the midbody. Bar, 10 µm.