The Effect of Histones on the Enzymatic Synthesis of Ribonucleic Acid

Abstract

Abstract The nature of the interaction between histones and deoxyribonucleic acid, and the effects of such complexes on the synthesis in vitro of ribonucleic acid, have been studied. Polycation inhibition of the RNA polymerase reaction appeared to be proportional to the adenine plus thymine content of the DNA primer. The extent of inhibition was also influenced by both the net positive charge and the size of the inhibitor. Aggregates were formed when the polycation reacted with the DNA primer in situ. The size of the aggregates was proportional to the concentration of polycation present. The RNA polymerase product formed in the presence of histones was both smaller and of different base ratio and sequence than the normal product formed in the absence of the inhibitor. Nearest neighbor frequency patterns of RNA formed from several different DNA primers under conditions of inhibition by different polycations have been reported. These results indicated that nearest neighbor frequency changes depended on the type of DNA primer as well as the type of inhibitor. There appeared to be no exact correlation between the effects of arginine- and lysine-rich histones and those of the related polycations, protamine and polylysine. The base composition and nearest neighbor frequencies of the RNA product formed under conditions of inhibition suggest that polycations can cause unequal copying of complementary sequences of the DNA primer.