Reproductive Medicine And Clinical Research

A novel human testis-specific gene, NYD-SP12, was identified by hybridizing human adult or fetal testes cDNA samples with human cDNA microarray containing 9,216 clones. NYD-SP12 cDNA (GenBank accession number: AF345909) consisted of 2,070bp. The predicted 1,707 bp open-reading fragment encoded a 569-aa protein.BLASTnr revealed that NYD-SP12 had a mouse homologue gene, which showed 88% and 77% identical level at nucleotide acid and amino acid, respectively. Microarray result showed that mRNA expression level of NYD-SP12 was thirty-fold higher in human adult testes than fetal testes. Similarly, semi-quantitative RT-PCR revealed a differential expression pattern of a NYD-SP12 homologous gene in mouse adult and infant testes.PCR and hybridization analysis of NYD-SP12 mRNA from multiple human tissues indicated the expression of NYD-SP12 exclusively in the testis. NYD-SP12 transcript was not detected in patients with spermatogenic arrest and Sertoli-cell-only syndrome. In situ hybridization revealed the expression of this gene was confined to spermatogenic epithelium but not interstitial cells. Furthermore, NYD-SP12 protein was detected in all spermatocytes and spermatids except for spermatogonia by using immunohistochemistry.Computerized SMART and Motif analysis revealed that the protein contained a SCOP domain in the C-terminus. In addition, the C-terminus of NYD-SP12 was also homologous to the C-terminus of Mea2, a protein located in the cytoplasmic motif of mouse Golgi membrane. Furthermore GeneRunner and ScanProsite predicted that NYD-SP12 had a cluster of phosphorylation sites for PKC, CK, and cAMP/cGMP-dependent protein kinase.Interestingly, the EGFP-NYD-SP12 fusion protein was localized to the Golgi apparatus. The positive signals were found in the acrosomal cap by immunohistochemistry using mouse- Anti-NYD-SP12 antibody.In conclusion, the results demonstrated that NYD-SP12 was involved in spermatogenesis, and suggested that the NYD-SP12-encoded protein might locate on the Golgi apparatus and play an important role in the formation of acrosome and fertilization.