Natural and synthetic polyanions are known to induce a wide spectrum of biochemical and physiological responses in mammalian cells.  Pyran copolymer, a synthetic polyanion (maleic anhydride/divinylether) is known to possess antiviral and antitumor activity.  Although the basis for these activities are thought to be related to the high molecular weight and polyanionic character of the molecule, the specific relationship and detailed mechanism is unknown.  The objective of this proposal is to establish the molecular basis for the physiological and pharmacological properties demonstrated by Pyran copolymer and other selected polyanions.  The methods used in this investigation will concentrate on the interaction of polyanions with nuclei isolated from mouse spleens.  The physical interaction of polyanions with the isolated nuclei will be analysed with small angle light scattering techniques.  The biochemical aspects will be examined through studies of DNA (in vivo) and RNA (in vitro) biosynthesis.  Finally, a chemical analysis of the nuclei will be made before and after treatment with the polyanions to determine any changes in the distribution of the nuclear components, DNA, RNA, and proteins.