Salt‐stable association of simian virus 40 capsid with simian virus 40 DNA

Abstract
In 8 M CsCl, a fraction of the wild-type previrions and tsB228 nucleoprotein complexes lose their core histones but retain their capsid. These histone-depleted complexes apear in the electron microscope as a protein shell attached to supercoiled DNA. Consistent with this result, we find that in l M NaCl, the wildtype previrions dissociate into two populations of nucleoprotein complexes. One population sediments between 50 and 140 S and morphologically resembles the shell-DNA complexes isolated in CsCl gradients. The other population is comprised primarily of nucleoproteins which sediment at 40 S.