RNF151 also termed as ring finger protein 151 is a 245 amino acid protein, which contains one Ring-type zinc finger and one TRAF-type zinc finger. RNF151, with, a putative nuclear localization signal (NLS)was exclusively expressed in the mouse testis and developmentally regulated during spermatogenesis. While RNF151 mRNA was present in round spermatids, its protein was expressed in elongating spermatids of the stage VIII-IX seminiferous tubules.