Spermatogenesis Associated Protein 21 (SPATA21)

Spergen-2, which has an open reading frame of 1500 nucleotides and encodes a protein of 500 amino acids that contains ankyrin repeat motifs and a putative nuclear localization signal. Expression of spergen-2 is developmentally upregulated in testis. In situ hybridization revealed that spergen-2 mRNA is expressed in spermatocytes and round spermatids (steps 1-6). Immunohistochemical analysis with confocal laser-scanning microscopy demonstrated that spergen-2 protein is predominantly expressed in nuclei of late spermatocytes (stages IX-XIV) and spermatids (steps 1-11), indicating the restricted expression of spergen-2 during spermatogenesis. In nucleoplasm of spermatogenic cell nuclei, spergen-2 tends to localize in the interchromosome space with relatively low DNA density.