Proviral DNA of Moloney Leukemia Virus: Purification and Visualization

Abstract
Closed-circular proviral DNA of Moloney leukemia virus has been purified from a 10(7) excess of cellular and mitochondrial DNA. The DNA can be visualized in the electron microscope and has the contour length of a molecule with a moleculecular weight of about 5.5 + 10(6). Electron microscopic observation of a hybrid between viral RNA and this circular DNA confirms the viral origin of this molecule.