βB2-crystallin protein is expressed in the testis and mature sperm. A, B: βB2-crystallin localization in the 4 week old mouse testis. A: βB2-crystallin (brown stain) is found at the basal surface of some but not all seminiferous tubules in cells having the round nuclei and scant cytoplasm diagnostic of the leptotene and zygotene spermatocytes. B: βB2-crystallin is only weakly detected in basal cells with ovoid nuclei characteristic of spermatogonia, but is easily observed in rounded acrosomal vesicles in contact with the nuclei of spermatids (arrowheads). C: Semi-quantitative rt-PCR analysis of βB2-crystallin mRNA expression in the testes during postnatal development. L-lens, 1,3,8,12,15,17, age of testis in days post natal. D: Western blot analysis of βB2-crystallin protein expression in sperm. WL-wildtype lens, PL- homozygous Crybb2Phil lens, WS- wildtype mouse sperm, PS- homozygous Crybb2Phil mouse sperm, BS- bovine sperm, HS- human sperm. A, bar=200 μm; B, bar=70 μm.