Fig. 3

Localization of PRAMEL1 in endoplasmic reticulum (ER), trans-Golgi network (TGN) and acroplaxome of spermatogenic cells. Heavy labeling of PRAMEL1 gold particles was observed in clusters in the rough ER (rER) (A), and light labeling was seen in some vesicles (B) in the cytoplasm of a spermatocyte. A low density of gold particles was detected in the Golgi apparatus (C), but not in acrosome granule (AG) and vesicle (AV) regions in early round spermatids (D, E). Along the development of acrosome and the formation of the TGN, a low density of PRAMEL1 labeling was seen in TGN of steps 3–4 round spermatids (E, F). Occasionally, a very few gold particles (arrowheads) were seen in the AG of steps 3–4 round spermatids (F, G). In contrast, a high density of PRAMEL1 labeling was seen in the acroplaxome region (yellow dotted line) at or cross the nuclear membrane of steps 4–6 spermatids (F, G). Unlabeled scale bar = 0.2 µm