Presence of synaptonemal complex protein 1 transversal filament-like protein in human primary spermatocytes

The synaptonemal complex (SC) is involved in the pairing of chromosomesduring meiosis. We found that antibodies raised against a protein component(P1) of the mouse synaptonemal complex, mouse SCP1, also identified the SCin human primary spermatocytes. Biopsies from 18 men presented withinfertility were evaluated by light-field microscopy and grouped into fivecategories: normal spermatogenesis, Sertoli cell-only syndrome, meioticdisturbances, spermiogenic (i.e. differentiation) disturbances, and othercombined disturbances. In all the normal subjects the SCP1 antibodydistinctly stained the synaptonemal complexes of primary spermatocytes,whereas Sertoli cells, spermatogonia or spermatids were never stained. Inthree of the groups, which had germ cells but showed spermatogenicdisturbances, the staining was similar to that seen in normal subjects. Insharp contrast to this, in sections from men with Sertoli cell-onlysyndrome no specific staining was seen. This study demonstrates that aSCP1-related protein is also conserved in the synaptonemal complex inmeiotic cells from man. Further studies will reveal to what extent theabsence or the non-functionality of SCP1 contributes to male infertility.