Biologic Properties of Polynucleotides . II

ECENT evidence suggests that it is possible to effect transformation of mammalian cells by exogenous nucleic acids.15 Thus the administration of large amounts of nucleic acids to humans as an’ experimental or therapeutic maneuver may be envisaged. Since little is known of the biologic properties of nucleic acids, apart from their pre-eminent role in directing protein synthesis and cell replication, a systematic investigation of such properties has been’ undertaken. Previous reports from this laboratory have been concerned with the potential antigenicity of nucleic acid,6 their interaction with serum albumin,79 and their anticomplementary properties.’#{176} In all these studies the synthetic ribopolynucleotides, as well as naturally occurring nucleic acids, have been examined, since the former offer an opportunity to observe the effects of variations in base composition and secondary structure on the biologic properties of these macromolecules. The anticoagulant properties of heparin are thought to derive largely from the strong negative charge endowed the heparin molecule by its many sulphate groups. Polynucleotides, by virtue of their phosphate groups, are also strong polyanions. For this reason attention was turned to the effects of polynucleotides upon the coagulation mechanism. The results demonstrate that certain polynucleotides do indeed possess anticoagulant properties; however, the evidence indicates that it is not the phosphate groups per se which bestow anticoagulant properties on a polynucleotide molecule, but rather that such properties are dependent upon base composition and secondary structure.