The function of Ensembl gene identifier ENSG00000099821 (POLRMT, RNA polymerase mitochondrial) is as follows. DNA-dependent RNA polymerase catalyzes the transcription of mitochondrial DNA into RNA using the four ribonucleoside triphosphates as substrates (PubMed:21278163, PubMed:33602924). Component of the mitochondrial transcription initiation complex, composed at least of TFB2M, TFAM and POLRMT that is required for basal transcription of mitochondrial DNA (PubMed:29149603). 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 (PubMed:29149603). Has DNA primase activity (PubMed:18685103, PubMed:33602924). 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) (PubMed:18685103, PubMed:33602924). {ECO:0000269|PubMed:18685103, ECO:0000269|PubMed:21278163, ECO:0000269|PubMed:29149603, ECO:0000269|PubMed:33602924}.