Phage DNA Directed Enzyme Synthesis in in vitro System from Yeast Mitochondria

Abstract

MITOCHONDRIA possess their own apparatus for protein synthesis¹ with rather bacteria-like properties^2–8. DNA dependent RNA polymerase from Neurospora crassa mitochondria was reported to be sensitive to rifampicin as is bacterial RNA polymerase⁹ (although work on other mitochondrial polymerases described rifampicin resistance^10,11). The molecular weight of this mitochondrial RNA polymerase was found to be surprisingly low (64,000)⁹ compared with bacterial polymerases (such as E. coli polymerase, 450,000). Does the sensitivity to rifampicin indicate a general similarity of mitochondrial polymerase and bacterial polymerases? We show here that RNA polymerase from mitochondria is able to mediate enzyme synthesis in vitro directed by DNA from the E. coli phages T3 and T7, and thus show that transcriptional signals for E. coli RNA polymerase can be recognized by the mitochondrial enzyme.