The role of clathrin-coated vesicles in acrosome formation.

Ultrastructural and cytochemical observations are presented which suggest that coated vesicles originating from the trans (distal) aspect of the rat spermatid Golgi apparatus transport lysosomal enzymes from the Golgi to the developing acrosome. Using an affinity purified antibody against the clathrin coats of pig brain coated vesicles, immunofluorescence and immuno-electron microscopic studies were carried out on frozen sections of rat seminiferous tubules. The results showed a specific labelling of the Golgi-acrosome region which corresponded precisely with the location of the coated vesicles in Epon sections. We conclude tht a least some of the coated vesicles in this region have clathrin coats.