This gene encodes a mitochondrial DNA-directed RNA polymerase. The gene product is responsible for mitochondrial gene expression as well as for providing RNA primers for initiation of replication of the mitochondrial genome. Although this polypeptide has the same function as the three nuclear DNA-directed RNA polymerases, it is more closely related to RNA polymerases of bacteriophage (including T7 RNA polymerase), mitochondrial polymerases of lower eukaryotes as well as chloroplastic RpoT polymerases.[6]
The structure of the enzyme has been solved. It exhibits an overall structure similar to that of phage RNAP, but the initiation mechanism is different in that it requires initiation factors TFAM (only in mammals) and TFB2M.[7] Elongation requires the elongation factor TEFM.[8] The exact termination process is less understood, but MTERF1 is thought to play a role.[9]
Maruyama K, Sugano S (1994). "Oligo-capping: a simple method to replace the cap structure of eukaryotic mRNAs with oligoribonucleotides". Gene. 138 (1–2): 171–4. doi:10.1016/0378-1119(94)90802-8. PMID8125298.
Suzuki Y, Yoshitomo-Nakagawa K, Maruyama K, et al. (1997). "Construction and characterization of a full length-enriched and a 5'-end-enriched cDNA library". Gene. 200 (1–2): 149–56. doi:10.1016/S0378-1119(97)00411-3. PMID9373149.
Falkenberg M, Gaspari M, Rantanen A, et al. (2002). "Mitochondrial transcription factors B1 and B2 activate transcription of human mtDNA". Nat. Genet. 31 (3): 289–94. doi:10.1038/ng909. PMID12068295. S2CID11164308.
Overview of all the structural information available in the PDB for UniProt: O00411 (Human DNA-directed RNA polymerase, mitochondrial (POLRMT)) at the PDBe-KB.