DNA polymerase specifically involved in the DNA repair by translesion synthesis (TLS) (PubMed:11297519). Plays an important role in translesion synthesis, where the normal high-fidelity DNA polymerases cannot proceed and DNA synthesis stalls (PubMed:11297519). Inserts one or 2 nucleotide(s) opposite the lesion (PubMed:11297519). During homologous recombination (HR) repair, has a overlapping role with the error-prone translesion polymerase PolZ1/DNApol-zeta to initiate repair synthesis that is completed by end joining or another polymerase that can bind and reinitiate synthesis (PubMed:22532806). Particularly important for the repair of UV-induced pyrimidine dimers and for hydroxyurea (HU)-induced DNA damage (PubMed:22532806, PubMed:24553286). Although inserts the correct base, may cause base transitions and transversions depending upon the context (By similarity). Forms a Schiff base with 5'-deoxyribose phosphate at abasic sites, but does not have any lyase activity, preventing the release of the 5'-deoxyribose phosphate (5'-dRP) residue (By similarity). This covalent trapping of the enzyme by the 5'-dRP residue inhibits its DNA synthetic activity during base excision repair, thereby avoiding high incidence of mutagenesis (By similarity). a 2'-deoxyribonucleoside 5'-triphosphate + DNA(n) = diphosphate + DNA(n+1) Binds 2 Mg(2+). Prefers Mg(2+), but can also use Mn(2+). In vitro, can also utilize other divalent cations such as Ca(2+). The enzyme in complex with the DNA substrate binds a third divalent metal cation. This binding is essential for catalyzing the DNA synthesis. Interacts (via C-terminus) with nopo. Localizes to interphase nuclei but undetectable during mitosis. Expressed in ovaries and testes. Expressed most highly in 0-2 hour embryos then at lower levels in larvae and pupae. The catalytic core consists of fingers, palm and thumb subdomains, but the fingers and thumb subdomains are much smaller than in high-fidelity polymerases; residues from five sequence motifs of the Y-family cluster around an active site cleft that can accommodate DNA and nucleotide substrates with relaxed geometric constraints, with consequently higher rates of misincorporation and low processivity. Ubiquitination enhanced by nopo. Viable and fertile (PubMed:24553286). Results in spindle defects (PubMed:24553286). Results in severe sensitivity of third-instar larvae to ultraviolet radiation (UV) (PubMed:22532806, PubMed:24553286). Exhibits a significant reduction in survival after hydroxyurea (HU)-induced DNA damage (PubMed:24553286). Decreases homologous recombination (HR) (PubMed:22532806). Simultaneous knockout of PolH/DNApol-eta and PolZ1/DNApol-zeta does not show any difference in the frequency of full HR repair compared to the single knockouts suggesting they have overlapping roles (PubMed:22532806). Belongs to the DNA polymerase type-Y family. Extended N-terminus.