Preparation of mouse spermatozoa

Caput and cauda epididymides were removed from mature male retired CD1 breeders and were placed in 2 ml of tris buffered saline (TBS) (pH 7.5–8) solution. Cuts were then made along the epididymis to allow the spermatozoa to swim out. The sperm solution was placed in Eppendorf tubes and washed through centrifugation twice at 1000 × g for 5 min. Spermatozoa were either used immediately or stored at –80˚C for future use. Testis extracts were obtained by removing the tunica albuginea from the testis of male retired CD1 breeders in 2 ml of 200 mM PBS. Cuts were then made in the seminiferous tubules to allow the spermatids to diffuse into the solution.