Effects of antinuclear autoantibodies on RNA polymerase.

DNA-dependent RNA polymerase was partially purified from wheat germ extract and tested for inhibition by antinuclear autoantibodies from the sera of patients with connective tissue diseases. The enzyme was inhibited by anti-DNA and by autoantibodies to the nuclear ribonucleoprotein nRNP. Autoantibodies to other ribonucleoproteins (Sm, Ro, La) did not cause inhibition. The enzyme preparation was shown to contain material with Ro and La antigenic activity but there was no nRNP or Sm detectable by immune precipitation. Previous work [3] has shown inhibition of prokaryotic (E. coli) RNA polymerase by anti-DNA, and our results show that the eukaryotic enzyme, in this case from wheat germ, is also inhibited. The results are consistent with the suggestion that inhibition by anti-DNA is due to template masking. Inhibition of RNA polymerase by antibodies to cellular ribonucleoprotein suggests that the antigen is in some way associated with the activity of the enzyme.