Figure 2.

SDS-PAGE of the insoluble (lane 1) and soluble (lane 2) protein after nuclease digestion of a chromatin-clarified nuclear sonicate. The insoluble (lane 3) and soluble (lane 4) protein formed in the presence of 0.2% mercaptoethanol. Insoluble filaments (lane 5) and soluble protein (lane 6) formed in the presence of 2% mercaptoethanol. Lane 7 shows filaments allowed to stand 5 h at room temperature in the presence of 2% mercaptoethanol. Lane 8 shows the protein solubilized by reducing agent. Insoluble (lane 9) and soluble (lane 10) protein after high-salt EDTA extraction is also shown. Essentially no protein is detected in lanes 4, 6, 8, and 10.