From: The replication machinery of LUCA: common origin of DNA replication and transcription
Polymerase family | Core catalytic domain | Organisms | Functions | DNA-RNA switches |
---|---|---|---|---|
DNA-directed DNAPs | ||||
 PolA | Derived RRM-Palm | Bacteria, some phages, mitochondria | Repair in bacteria, replication in some phages, plant and fungal mitochondria, and mitochondrial plasmids | From DNAP to single-subunit RNAP in phages |
 PolB | RRM-Palm | Archaea, eukaryotes, some bacteria, many large DNA viruses | Replication in Crenarchaeota, eukaryotes, viruses; repair in other archaea, bacteria | To DNA template and product at origin(?) |
 PolC | Polβ-like nucleotidyl-transferase | Bacteria, a few phages | Replication | PolyA polymerase in eukaryotes |
 PolD | 2xDPBB in a single protein | Archaea except for crenarchaea and some thaumarchaea | Replication | To DNA template and product at origin(?) |
 AEP | RRM-Palm | Archaea, eukaryotes, some bacteria, diverse mobile elements, many large DNA viruses | RNA priming of replication in archaea, eukaryotes, and dsDNA viruses; replication of plasmids and phages | From RNA synthesis during priming to DNA synthesis during plasmid replication |
DNA-directed RNAPs | ||||
 Two-DPBB RNAP, two subunits | 2xDPBB, one in each subunit | Bacteria, archaea, eukaryotes, many large DNA viruses | Transcription | To DNA template at origin(?) Viroid replication: to RNA template |
 Two-DPBB RNAP, single subunit | 2xDPBB in a single protein | Many phages and linear cytoplasmic plasmids of fungi | Transcription | Eukaryotic RNAi: to RNA template |
 Single-subunit RNAPs | Derived RRM-Palm | Some phages, mitochondria | Transcription | None |
RdRP-RT | ||||
 RdRP | RRM-Palm | RNA viruses | Replication | To DNA synthesis in RT(?) |
 RT | RRM-Palm | Retroelements, reverse-transcribing viruses | Replication in viruses and retroelements; telomere synthesis in eukaryotes | Using both RNA and DNA templates |
 RNAi eRdRP | 2xDPBB in a single protein | Eukaryotes | Small RNA amplification | None |