A Hybrid Helix Containing Both Deoxyribose and Ribose Polynucleotides and Its Relation to the Transfer of Information between the Nucleic Acids.

Oneof the central problems in molecular biology today is the mechanism whereby genetic information which is stored in the deoxyribosenucleic acid (DNA) is transferred to other molecular species. It is quite clear that genetic information is contained in the DNA molecules. This was initially demonstrated by work on the bacterial transforming factor and more recently by the analysis of the mechanism of bacteriophage infection. It is equally clear at the present time that the major mode of expressing a genetic potentiality is by governing protein synthesis. Protein synthesis is carried out in the microsomal particles. However, the information bearing elements in protein synthesis are believed to be found in the ribosenucleic acid (RNA), which constitutes over one half of the microsomal particle. The other component of these particles is protein, and it is unlikely that this has an important role in ordering the sequence of amino acids because the microsomal protein component seems to be common to. all particles even though they are synthesizing widely different proteins.' This has led to the hypothesis that DNA "makes" RNA. The implication in this statement is that there exists a mechanism whereby the DNA molecule can act as a template for determining the order of ribonucleotides, so that the DNA nucleotide sequence (hence information) is related to that found in the RNA molecule. Up to the present there has been no experimental evidence regarding the mechanism of this transfer. The purpose of this paper is to show that it is possible to form a specific and complementary helical complex involving a synthetic DNA strand and a synthetic RNA strand. In this we demonstrate that this is a possible method for the transfer of the information from DNA to RNA. Synthetic polynucleotides were used in carrying out this study. For several years, the synthetic polyribonucleotides have been available as a result of the work of Ochoa and his collaborators on the enzyme polynucleotide phosphorylase.2 In the presence of a proper substrate, this enzyme has the ability to polymerize a variety of nucleotides which have the same ribosephosphate backbone as that found in naturally occurring RNA. These materials have been extremely useful in carrying out a variety of experiments on polynucleotide interaction. In particular, it has been possible to demonstrate with them the formation of a variety of two and three stranded helical complexes, such as polyriboadenylic acid plus one or two strands of polyribouridylic acid.3 4 More recently synthetic polynucleotides containing the deoxyribose backbone have been polymerized by Khorana and his associates.Using a new polymerization mechanism, they have been able to make a series of deoxyribose polymers with chains containing up to 20 residues. Although these are considerably shorter than many of the synthetic polyribonucleotides, nonetheless it was decided to attempt to form helical complexes with these materials.