Ribonucleic Acid Synthesis in Plant Mitochondria: Effects of Some Inhibitors and Cyclic Nucleotides

Abstract

Mitochondria isolated from 48-h germinating Vigna sinensis (L.) Savi can incorporate ['HJuridine into acid-insoluble material. The incorporation is highly sensitive to rifampicin and partially so to ethidium bromide, two specific inhibitors of template function. The inhibitory effect of rifampicin can be partly counteracted by cyclic 3':5'-AMPbut not by cyclic 3':5'-GMP, if they are allowed to interact with the synthetic system before the treatment with rifampicin. This indicates that cyclic AMP and rifampicin compete for a common site on the RNA polymerase responsible for DNA-dependent RNA synthesis. Inhibition by ethidium bromide is unaffected by prior nucleotide interaction with the system.