module: dmel_dna_polymerase_complexes
title: B-family DNA polymerase complexes and DNA polymerase gamma in Drosophila melanogaster
label: DNA polymerase complexes
module_type: PROTEIN_COMPLEX
description: >-
  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.
summary: >-
  Pol alpha-primase, Pol delta, Pol epsilon, Pol zeta and the mitochondrial
  Pol gamma holoenzymes.
concepts:
  - {id: GO:0042575, label: DNA polymerase complex}
parts:
  - id: pol_alpha_primase
    label: DNA polymerase alpha-primase
    role: primer synthesis
    description: >-
      Four-subunit complex of the Pol alpha catalytic subunit (PolA1), its B
      subunit (PolA2) and the small (Prim1) and large (Prim2) primase subunits.
    group: DNAPOLA
    complex_term: {id: GO:0005658, label: "alpha DNA polymerase:primase complex"}
    unit_functions:
      PolA1: {id: GO:0003887, label: DNA-directed DNA polymerase activity}
    processes:
      - {id: GO:0006269, label: "DNA replication, synthesis of primer"}
  - id: pol_epsilon
    label: DNA polymerase epsilon
    role: leading-strand polymerase
    group: DNAPOLE
    complex_term: {id: GO:0008622, label: epsilon DNA polymerase complex}
    unit_functions:
      PolE1: {id: GO:0003887, label: DNA-directed DNA polymerase activity}
    processes:
      - {id: GO:0006260, label: DNA replication}
  - id: pol_delta
    label: DNA polymerase delta
    role: lagging-strand polymerase
    group: DNAPOLD
    complex_term: {id: GO:0043625, label: delta DNA polymerase complex}
    unit_functions:
      PolD1: {id: GO:0003887, label: DNA-directed DNA polymerase activity}
    processes:
      - {id: GO:0006260, label: DNA replication}
  - id: pol_zeta
    label: DNA polymerase zeta
    role: translesion polymerase
    description: PolZ1 (Rev3) and PolZ2 (Rev7) with the shared Pol delta subunits PolD2 and PolD3.
    group: DNAPOLZ
    complex_term: {id: GO:0016035, label: zeta DNA polymerase complex}
    unit_functions:
      PolZ1: {id: GO:0003887, label: DNA-directed DNA polymerase activity}
    processes:
      - {id: GO:0019985, label: translesion synthesis}
  - id: pol_gamma
    label: DNA polymerase gamma
    role: mitochondrial DNA polymerase
    group: DNAPOLG
    complex_term: {id: GO:0005760, label: gamma DNA polymerase complex}
    unit_functions:
      PolG1: {id: GO:0003887, label: DNA-directed DNA polymerase activity}
    processes:
      - {id: GO:0006264, label: mitochondrial DNA replication}
notes: >-
  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.