Localization of the DAZ gene expression in seminiferous tubules of patients with spermatogenic disorders.

The research on the expression and mutations of DAZ and its homologues in human and other mammals suggests that protein products of these genes can mainly affect development of germinal cells. The aim of the present study was to analyze the expression of the DAZ gene in seminiferous tubules of six men with spermatogenic disorders (hypospermatogenesis and spermatogenic arrest). The results based on the RT-PCR IS technique demonstrated that the DAZ product was present only in some seminiferous tubules and the fluorescence intensity was different within individual tubules. The most intense fluorescence characterised the spermatogonia, especially these organised in small groups inside separate tubules. In the patients with spermatogenic arrest at the spermatocyte stage, the DAZ gene transcripts were also found in primary spermatocytes. However, the fluorescence intensity of primary spermatocytes, except the fluorescence of the spermatocytes localised upon the lumen, was weaker than the fluorescence of spermatogonia. The results of our study showed that DAZ gene activity seems to correspond to the proliferative activity of stem cells of germinal epithelium.