Figure 3:

SUMO-2/3 is identified in human pachytene spermatocytes.

Meiotic spermatocytes were triple-labeled for SUMO-2/3 (green), SCP3 (red) and centromere (blue). SUMO-2/3 is detected in a scattered pattern in meiosis as early as leptotene (A). In some pachytene cells (B–F), SUMO-2/3 (alone in B, merged with centromeres in C, and merged with SCs and centromeres in E) appears as a bright, dense cloud at, or near, the centromere of human chromosome 9 (magenta FISH signal in F); smaller and lighter signals associate with the sex body (arrowhead) and the centromeric region of an unidentified chromosome. In a second pachytene cell (G–L), SUMO-2/3 forms small punctate foci similar to meiotic centromeres (G and J); merging the two images (I and L) shows complete co-localization of both signals at all centromeres. This cell also has a small, brightly stained focal association (arrow). SCs and centromeres are shown in D and K, respectively. All images, ×1000.