Immunolocalization of SCP1 (Green), Centromeres (Red), and Staining of the Chromatin with DAPI (Blue)

<div><p>Several focal planes are superimposed and projected in a single plane in each picture.</p><p>(A–C) Pachytene. SCP1 appears as continuous lines along autosomes and is completely absent on the sex chromosomes. (A' and C'). Detailed view of the sex chromosomes in the same cell.</p><p>(D–F) Diplotene. SCP1 mostly appears as fragmented lines that run along chromosomes. These lines are continuous in some regions. SCP1 remains associated at the centromeric regions of autosomes and also appears associated to the X chromosome centromere (arrowheads). A structure labeled with SCP1 appears at the periphery of the sex body (arrow). (D' and F') At a higher magnification this structure is clearly detected near the centromere of the Y chromosome.</p><p>(G–I) Prometaphase I. SCP1 signal has completely disappeared from the chromosomes. However, a small structure is clearly labeled (arrow). Bivalents are not oriented at the metaphase plate. Sex chromosomes (X, Y) are clearly discernible, and they remain associated. (G' and I'). Enlargement of the sex chromosomes. The SCP1-labeled structure appears at the region of contact between sex chromosomes (arrow).</p><p>(J–L) Metaphase I. The SCP1-labeled structure is present in the region where sex chromosomes (X, Y) are located. (J'–L') At a higher magnification it can be seen that the SCP1-labeled structure (arrow) is associated to the sex chromosomes.</p><p>(M–O). Anaphase I. Homologous chromosomes have segregated and the SCP1-labeled structure is still visible (arrow). However, it does not maintain any association with the chromatin masses near the cell poles. Bar: 5 μm in (A–O); 1 μm in (A'–L').</p>