Structures of polyoma virus: on the histone component and virion core

We have observed that purified polyoma virus is able to take up an amount of calf thymus histone equivalent to 10 to 50% of its normal histone content under conditions allowing the binding of considerably lesser amounts of several other proteins. Some of the bound histone could not be released by procedures procedures routinely used for virus purification. We have also found that some of the histone present in purified polyoma virus could be selectively released without major breakdown of virus particles. Possible models for virus structure are discussed in the light of the present and other recent data.