Template Specificity of Oligonucleotides for Ribonucleic Acid Polymerase.

Recently attempts have been made to d&m: chemically the templates used as substrates in bacterial ribonucleic acid polymerase systems and to analyze the RX.1 products of such systems (l-9). Enzymatically synthesized polydeosynucleotides (2, 3, 6, 8) and polyribonucleotides (5, 7, 9, 10) permitted studies of the mechanism involved in the polyribonucleotide synthesis. It has been shown that an RXA polymerase preparation from Escherichia coli catalyzes the synthesis of polyadenylate dependent upon added chemically synthesized oligodeosythymidylate (1, 3, 11-13). The poly A1 product has been employed in an amino acid incorporating system in vitro to direct the synthesis of polylysine (12, 13). Our studies indicated that enzyme activities other than the template-copying activity existed in our RN.1 polymerase prep arations. This was apparent when it was found that the chain length of the poly A was longer than that of the d(pT)1G14 used as the primer. If this system is to realize its full potential fol the investigation of protcin biosynthesis at the level of translation of genetic information into protein, it is desirable to produce oligoribonurleotides exactly complementary to the oligodeoxynucleotide template. We have, therefore, investigated further the template-copying activity of RN.1 polymerasc preparations with the use of both oligodeoxynucleot,ides and oligoribonucleotides. Methods were devised to suppress contaminating enzyme activities such as polynucleotide phosphorylasc and poly A synthetase (4, 14-17). With our modified conditions we ronfirmed the template-copying activity of bacterial RNA polymerase. In addition, the use of natural and synthetic oligodeoxynucleotide copolymers gave rise to oligoribonucleotide copolymers. Analysis of chain lengths, however, still indicated the production of oligoribonucleotides longer than the oligodeosynucleotide templates.