B-family DNA polymerase complexes and DNA polymerase gamma in Drosophila melanogaster

Eukaryotic genome replication uses three multisubunit B-family DNA polymerases. DNA polymerase alpha-primase synthesizes the RNA-DNA primers that start leading and lagging strands. DNA polymerase epsilon extends the leading strand and DNA polymerase delta extends the lagging strand and matures Okazaki fragments; both have 3'-5' proofreading exonuclease activity. DNA polymerase zeta, made of the catalytic subunit Rev3 (PolZ1), Rev7 (PolZ2) and the two Pol delta accessory subunits, performs translesion synthesis past DNA damage. DNA polymerase gamma, a family A enzyme made of a catalytic subunit and an accessory subunit, replicates mitochondrial DNA.

The parts are distinct holoenzymes that FlyBase groups together; they are alternative polymerases, not one complex. PolD2 and PolD3 are shared by Pol delta and Pol zeta. Pol gamma also appears in dmel_mitochondrial_dna_replisome. Chrac-14 is the Pol epsilon subunit 3 and is also a subunit of the CHRAC chromatin-remodelling complex. Primase activity is not assigned as a GO function because the GO term for DNA primase activity is obsolete. FlyBase groups realized by this module: DNAPOL (FBgg0001200). Subgroups folded into it: DNAPOLA, DNAPOLE, DNAPOLD, DNAPOLZ, DNAPOLG. Participants were generated from the FlyBase gene-group membership and mapped to UniProtKB by projects/FLYBASE_GENE_GROUPS/generate_modules.py from module_specs/dmel_dna_polymerase_complexes.yaml. Member genes with a gene review in this repository: PolG1, PolG2.