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

Abstract

The synaptonemal complex (SC) is involved in the pairing of chromosomes during meiosis. We found that antibodies raised against a protein component (P1) of the mouse synaptonemal complex, mouse SCP1, also identified the SC in human primary spermatocytes. Biopsies from 18 men presented with infertility were evaluated by light-field microscopy and grouped into five categories: normal spermatogenesis, Sertoli cell-only syndrome, meiotic disturbances, spermiogenic (i.e. differentiation) disturbances, and other combined disturbances. In all the normal subjects the SCP1 antibody distinctly stained the synaptonemal complexes of primary spermatocytes, whereas Sertoli cells, spermatogonia or spermatids were never stained. In three of the groups, which had germ cells but showed spermatogenic disturbances, the staining was similar to that seen in normal subjects. In sharp contrast to this, in sections from men with Sertoli cell-only syndrome no specific staining was seen. This study demonstrates that a SCP1-related protein is also conserved in the synaptonemal complex in meiotic cells from man. Further studies will reveal to what extent the absence or the non-functionality of SCP1 contributes to male infertility.

Baseline expression profile of meiotic-specific genes in healthy fertile males

“…According to our data, only four of these genes (SYCP1, SPO11, MSH4, and MSH5) are exclusively expressed in germ cells (fertile males), showing similar expression levels (between 1-and 1.5-fold the expression of its calibrator) among individuals studied. To our knowledge, no quantitative expression analysis regarding these four genes has been done, but immunofluorescent studies performed in humans have demonstrated that the expression of SYCP1, SPO11, MSH4, and MSH5 genes is restricted to the germ cells in testis (24,31,32), which is in agreement with our results. In knockout mice, Sycp1 À/À (25) and Spo11 À/À (33,34) spermatocytes are arrested at early pachytene and are unable to form the synaptonemal complex.…”

Reactivity of Germ Cell Maturation Stage-Specific Markers in Spermatocytic Seminoma: Diagnostic and Etiological Implications

“…These include SCP1, a protein involved in the pairing of homologous chromosomes, which is present in the meiotic prophase of both rodent and human spermatocytes (Meuwissen et al, 1992;Pousette et al, 1997;Sage et al, 1999;Schmekel et al, 1996). Our immunohistochemical results demonstrated that the protein is indeed present in primary and pachytene spermatocytes.…”

“…Recently, specific antibodies for SSX (recognizing subtypes 2-4) and SCP1 have been reported (Dos Santos et al, 2000;Meuwissen et al, 1992;Pousette et al, 1997;Schmekel et al, 1996). They were found to stain certain stages of male germ cell development in rodent (Heyting et al, 1989;Meuwissen et al, 1992) and human (Dos Santos et al, 2000; Pousette et al, 1997), in particular spermatogonia and primary spermatocytes.…”

Kinetics of meiosis in azoospermic males: a joint histological and cytological approach

“…For example, Pousette et al (1997) used anti-SCP1 and Metzler-Guillemain et al (2000) used anti-SCP1 and anti-SCP-3. However, if only these antibodies are used, asynaptic pachytene spermatocytes cannot be separated from late zygotene and early diplotene stages.…”