Fig. 1. Immunolocalization of TIF1ß in post-pubertal wild-type testis. Frozen histological sections were incubated with the anti-TIF1ß antibody whose binding to cell structures was then revealed with a Cy3-conjugated secondary antibody (red signal) and nuclei were counterstained with DAPI (blue signal). (A,D,G,J) Cy3 and (B,E,H,K) DAPI labeling.(C,F,I,L) Superimposition of the two fluorochromes. (G-L) Single optical sections of confocal microscopic analysis. Roman numerals refer to stages of the seminiferous epithelium cycle (Russell et al., 1990). Each stage is defined by a specific association of germ cell types. The cycle corresponds to the series of changes occurring at a given level of the seminiferous tubule between two successive appearances of the same cell association. In normal mice, there are 12 stages, designated I to XII, each corresponding to one of the first 12 steps of spermatid maturation. ES-9 and ES-13 correspond to steps in spermatid maturation. Ch, meiotic chromosomes; L, leptotene spermatocytes; P, pachytene spermatocytes; Nu, nucleolus of Sertoli cell; RS, round spermatids; S, Sertoli cells; Sa, satellite nucleolar heterochromatin of the Sertoli cell. The arrowheads and arrows in A-F indicate heterochromatin- and chromosome-associated TIF1ß, respectively. The broken lines indicate the contours of seminiferous tubules. Scale bar: 30 µm in A-C; 15 µm in D-F; 3 µm in G-L.