DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Combines in the mitochondrion with mitochondrial transcription factor mtf1 as a holoenzyme to recognize and initiate transcription at the core mitochondrial promoters. a ribonucleoside 5'-triphosphate + RNA(n) = diphosphate + RNA(n+1) Belongs to the phage and mitochondrial RNA polymerase family.