Ribonucleic Acid-dependent Ribonucleotide Incorporation

Abstract

Several enzymatic reactions are known to utilize ribonucleoside triphosphates for incorporation of ribonucleotides into ribonucleic acid polymers. Two of these reactions have been well characterized. In one, cytidine 5’-phosphate and adenosine 5’-phosphate are added to the nucleoside terminal end of soluble RNA, forming an amino acid acceptor RNA terminated by the trinucleotide sequence, pCpCpA (14). The other is a deoxyribonucleic acid-dependent reaction, the product of which is an RNA with base ratios complementary to the primer DNA (5-S). In addition, other less well characterized reactions have been reported; in these, chiefly a single ribonucleoside monophosphate is incorporated, either as end addition or in endonucleotide linkage (9-14). It is the purpose of this communication to report the purification and characterization of an enzyme obtained from ribonucleoprotein particles of Escherichia COG that catalyzes an RNAdependent incorporation of ribonucleotides. The product of the reaction is primarily a polyriboadenylate polymer.