Molecular cloning of protamine-2 and expression with aging in Japanese monkey (Macaca fuscata)

In order to isolate genes relating spermatogenesis with postnatal development and aging, we have attempted to obtain genes showing differences in expression in testis of Japanese monkeys ( Macaca fuscata) by means of differential display PCR, and we have cloned, sequenced and characterized protamine-2 (PRM2) of Japanese monkey. The predicted open reading frame encoded a protein of 103 amino acid residues, most of which are common to those of other mammals. Northern analysis revealed that the PRM2 gene is expressed at adult and aged stages, but not at the juvenile stage. In situ hybridization revealed that the PRM2 gene is expressed mainly in late spermatids and its expressional potential is decreased from adult to aged stages. It suggests that PRM2 in spermiogenesis is mediated by the age of the animal.