In Vitro Synthesis of Ribosomal Ribonucleic Acid by a Deoxyribonucleic Acid-Protein Complex Isolated from Escherichia coli

A DNA-RNA polymerase complex has been isolated from EDTA-treated Escherichia coli MRE 600. This fraction contains virtually all of the RNA synthetic capacity expressed in the EDTA-treated cells. The in vitro synthesis is sensitive to rifampicin, indicating that the complex is actively initiating RNA chains. Analysis of the product RNA by hybridization competition shows that between 20 to 30% is rRNA. Guanosine tetraphosphate (ppGpp) inhibits global RNA and rRNA synthesis equally, and no preferential inhibition of rRNA synthesis is detected.