An optimised STAPUT method for the purification of mouse spermatocyte and spermatid populations

The purification of individual male germ cell populations is integral for the molecular and biochemical characterisation of specific spermatogenic phases. Although a number of more contemporary techniques have been developed, velocity sedimentation using the STAPUT method remains as a gold standard for this purpose. The gentle nature of the technique, wherein germ cell subpopulations are separated by sedimentation at unit gravity, results in the isolation of viable and high-purity cells. We provide an updated and simplified step-by-step version of the STAPUT protocol for the purification of mouse male germ cells. As per the original method, the protocol described herein allows for the purification of mouse spermatocyte and round spermatids, however it also allows for successful purification of elongating, and elongated spermatid populations, and is optimised for the preservation of cellular ultrastructure. This method yields sufficient numbers of high-purity cells from one adult mouse for RNA or protein extraction or for immunolocalisation studies.