Deoxyribonucleic acid-dependent ribonucleic acid polymerase activity in purified trachoma elementary bodies: effect of sodium chloride on ribonucleic acid transcription.

Highly purified trachoma elementary bodies (T'ang strain), incubated in the presence of the four nucleoside triphosphates [Mg(2+), Mn(2+), 2-mercaptoethanol, tris(hydroxymethyl)aminomethane buffer (pH 7.5)] were found to incorporate (3)H-uridine triphosphate (UTP) into ribonucleic acid (RNA) molecules. Eighty-seven per cent of the labeled molecules were sensitive to ribonuclease treatment. In vitro RNA synthesis was almost completely inhibited by actinomycin D. Rifampin was also inhibitory, but allowed some initial RNA synthesis before complete inhibition occurred. When the reaction mixture lacked Mn(2+), trachoma elementary bodies synthesized, for a limited period, high-molecular-weight RNA species (23 to 24S, 16 to 17S, and 10 to 11S). Addition of 0.2 m NaCl to the same reaction mixture stimulated and prolonged (3)H-UTP incorporation into the same radioactive RNA species. Addition of 0.001 m Mn(2+) instead of NaCl also stimulated (3)H-UTP incorporation but prevented the synthesis of the high-molecular-weight RNA species.