ABSTRACT
Stimulated by retinoic acid gene 8 (STRA8) is specifically expressed in mammalian germ cells before their transition from mitosis to meiosis. STRA8 expression is observed only in the postnatal testis. Single nucleotide polymorphisms but no mutations were identified in the coding or proximal promoter region of STRA8 in some gonadal dysgenesis patients. Studies on the teratocarcinoma cells and embryonic stem cells (ESC) transfected with STRA8-EGFP, a fusion construct harboring the promoter and coding region of the enhanced green fluorescence protein, have shown that the STRA8-EGFP positive cells may undergo meiosis, develop into sperm and generate live offspring mice. STRA8-EGFP positive cells derived from the bone marrow are able to differentiate into spermatogenic cells, but arrest in the premeiotic stage, and those from the adult mouse testis, when cultured in ESC culture conditions, may acquire ESC properties, pluripotency and redifferentiation capacity and act as a new stem cell source for tissue regeneration. The presence of oocytes renewed in postnatal mouse ovaries calls in question the absence of STRA8 in postnatal mouse ovaries.