Figure 1.

Fates of Mammalian Sperm Nuclei when the Protamines are Extracted. When mammalian sperm nuclei are extracted with high salt and dithiothreitol (DTT) to extract the protamines, they decondense completely, leaving only the nuclear annulus (D-F). When sperm are washed with SDS before salt extraction, the nuclear matrix remains intact (A-C) and DNA loop domains are visible. This figure was originally published in [25].