Ankyrin Repeat, SAM And Basic Leucine Zipper Domain Containing Protein 1 (ASZ1)

The deduced 475-amino acid protein contains 4 tandem ankyrin (ANK) repeats in its N-terminal half, followed by a central sterile-alpha motif (SAM) and a putative C-terminal basic leucine zipper (bZIP) domain. Human ASZ1 shares 99.2 and 85.3% amino acid identity with the chimpanzee and mouse orthologs, respectively. Northern blot and semiquantitative RT-PCR analyses of mouse and human tissues detected ASZ1 expression exclusively in testis and ovary. In mouse, Asz1 expression was higher in newborn and young ovary than in adult ovary. In situ hybridization and immunohistochemical analysis of mouse tissues localized Asz1 mainly to the cytoplasm of pachytene spermatocytes and early spermatids, in oocytes at all stages of oogenesis, and in early preimplantation embryos.