Figure 7.

Basic nuclear proteins from epididymal sperm from wild-type, heterozygous, and Tnp1−/− mice (129 background) and SRS from wild-type mice. Protein yields per cell were roughly similar for the three genotypes. Partially processed forms of P2 are labeled according to the convention in Fig. 5. That these bands are indeed protamines was confirmed by their insolubility in SDS (27). Part of the epididymal preparations were treated with ethyleneimine (+EI) (28) to separate P1 and the mature form of P2.