Localisation of lanosterol 14α-demethylase in round and elongated spermatids of the mouse testis: an immunoelectron microscopic and stereological study

Abstract

Lanosterol 14α-demethylase (CYP51) is a microsomal cytochrome P450 enzyme involved in the postsqualene cholesterol biosynthetic pathway. CYP51 removes 14α-methyl group from lanosterol], forming FF-MAS (folicular fluid meiosis activating sterol) which accumulates in gonads. The goal of our study is to determine the expression of CYP51 protein in the male gonad. Using electron microscopic immunogold techniques, CYP51 is localised on inner and outer acrosomal membranes of male germ cells, the round and elongated spermatids. Significance of CYP51 localization on the acrosome which is a Golgi-derived organelle is not known, but we propose that CYP51-formed FF-MAS can function as a signalling sterol during fertilisation.