This family consists of several mammalian male enhanced antigen 1 (MEA1) proteins. The Mea-1 gene is found to be localised in primary and secondary spermatocytes and spermatids, but the protein products are detected only in spermatids. Intensive transcription of Mea-1 gene and specific localisation of the gene product suggest that Mea-1 may play a important role in the late stage of spermatogenesis [].