Studies on Polynucleotides

Abstract

The transcription of three short synthetic bihelical DNA's of defined sequence was studied with RNA polymerase of Escherichia coli. DNA-I is a completely base-paired duplex, DNA-II contains a single-stranded portion with a 3′-hydroxyl end group while DNA-III contains a protruding single-stranded region with a 5′-hydroxyl end group. All the three DNA's were transcribed by the polymerase but the RNA formed was heterogeneous. Initiation occurred at multiple sites with purine nucleoside triphosphates and there was evidence that both strands were transcribed. A part of the RNA formed had higher molecular weight than the template strands. Attempts to control initiation by using a complementary ribo-oligonucleotide primer and also rifampicin were only partially successful.