Error-free DNA polymerase specifically involved in DNA repair. Plays an important role in translesion synthesis (TLS), where the normal high fidelity DNA polymerases cannot proceed and DNA synthesis stalls. Plays an important role in the repair of UV-induced pyrimidine dimers and confers resistance to ultraviolet light. Depending on the context, it inserts the correct base, but may cause base transitions and transversions. Forms a Schiff base with 5'-deoxyribose phosphate at abasic sites, but does not have lyase activity. Targets POLI to replication foci. Exhibits cyclobutane dimer nonmutagenic bypass activity in vitro. 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. The binding of this third divalent cation, which is coordinated by water molecules and two oxygen atoms from DNA and dNTP, is essential for catalyzing the DNA synthesis. Optimum temperature is 22 degrees Celsius. Interacts with PCNA1 and PCNA2. The interaction with PCNA2 is required for translesion synthesis (TLS) to repair UV photoproducts. Accumulates at replication forks after DNA damage. Constitutively expressed in roots, stems, leaves, flowers and siliques. 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. Enhanced sensitivity to UV radiation accompanied by an increased mutation frequency. Shorter root and stem growth. Belongs to the DNA polymerase type-Y family.