RNA synthesis in nuclei isolated from normal and Friend virus-infected mouse spleen.

Spleen nuclei were isolated and purified from normal and Friend virus-infected mice. Nuclei from infected spleen were found to contain almost 3 times as much RNA as nuclei from normal spleen. RNA polymerase activity of normal and Friend virus-infected nuclei were compared. Optimal reaction condi tions at high and low ionic strength were determined and were found to be similar to normal rat liver nuclei. While the RNA polymerase activity of both normal and Friend virus-infected nÃ1clei was stimulated at high ionic strength, the level of activity of the nuclei from normal spleen reached only 25% of the activity of the infected spleen nuclei. It is suggested that the difference noted in RNA polymerase activity was not simply a result of increased DNA template activity, but rather an increase in the amount of enzyme present in the infected cells.