DNA-dependent RNA polymerase catalyzes the transcription of mitochondrial DNA into RNA using the four ribonucleoside triphosphates as substrates (, ). Component of the mitochondrial transcription initiation complex, composed at least of TFB2M, TFAM and POLRMT that is required for basal transcription of mitochondrial DNA . In this complex, TFAM recruits POLRMT to a specific promoter whereas TFB2M induces structural changes in POLRMT to enable promoter opening and trapping of the DNA non-template strand . Has DNA primase activity (, ). Catalyzes the synthesis of short RNA primers that are necessary for the initiation of lagging-strand DNA synthesis from the origin of light-strand DNA replication (OriL) (, ).
Subcellular locations: Mitochondrion