Inhibition of RNA Polymerase III by N -Hydroxy-2-Acetylaminofluorene

Abstract

Abstract

Parenteral administration of the potent hepatocarcinogen N-hydroxy-2-acetylaminofluorene to rats results in a substantial inhibition of hepatic RNA polymerase III(C), the enzyme responsible for the synthesis of tRNA and 5 S RNA. The minor component of RNA polymerase III extractable from nuclei shows a 45-65% reduction in activity while the major component of the enzyme extractable from cytoplasm shows a 40-65% inhibition. This reduction of RNA polymerase III activity is sufficient to account for the inhibition of rRNA synthesis produced by administration of the carcinogen in vivo.