INFLUENCE OF IONIC STRENGTH AND A POLYANION ON TRANSCRIPTION IN VITRO .2. EFFECTS ON TEMPLATE EFFICIENCY OF RAT LIVER CHROMATIN FOR A PURIFIED BACTERIAL RNA POLYMERASE

The effect of ammonium sulphate or polyethylene sulphonate on RNA synthesis catalyzed by Escherichia coli RNA polymerase was investigated using rat liver chromatin as template. With the enzyme in a transcription complex, addition of ammonium sulphate or polyethylene sulphonate allowed the transcription of the whole DNA, as shown by kinetic and nearest-neighbor base frequency analyses. Although we were able to confirm that rat liver chromatin was capable of binding as many RNA polymerase molecules as deproteinized rat liver DNA, we have observed a relative increase in the template efficiency of the chromatin as its concentration was decreased in the incubation mixture. On the other hand, the RNA synthesized with rat liver chromatin as template had a base composition and nearest-neighbor base frequencies more DNA-like than those of the RNA's synthesized by rat liver aggregate RNA polymerase and all the RNA's so far isolated from rat liver nuclei. These observations bring into question the exact physiological meaning of the template properties of isolated rat liver chromatin. © 1968.