Organization and modulation of a novel nuclear phosphoprotein during rat spermatogenesis.

The localization and distribution of the B2 nuclear phosphoprotein in spermatogenesis in the rat were studied by immuno-gold electron microscopy. In spermiogenesis, the phosphoprotein B2 was shown to have phase-dependent changes in number and distribution. A temporal increase in synthesis of this protein was observed during spermiogenesis. The high quantity of this protein in the mature sperm head suggests its role in maintenance and organization of DNA.