DNA polymerase that promotes microhomology-mediated end-joining (MMEJ), an alternative non-homologous end-joining (NHEJ) machinery triggered in response to double-strand breaks in DNA. MMEJ is an error-prone repair pathway that produces deletions of sequences from the strand being repaired and promotes genomic rearrangements, such as telomere fusions, some of them leading to cellular transformation (PubMed:25275444, PubMed:25642963). POLQ acts as an inhibitor of homology-recombination repair (HR) pathway by limiting RAD51 accumulation at resected ends (PubMed:25642963). POLQ-mediated MMEJ may be required to promote the survival of cells with a compromised HR repair pathway, thereby preventing genomic havoc by resolving unrepaired lesions (PubMed:25642963). The polymerase acts by binding directly the 2 ends of resected double-strand breaks, allowing microhomologous sequences in the overhangs to form base pairs. It then extends each strand from the base-paired region using the opposing overhang as a template. Requires partially resected DNA containing 2 to 6 base pairs of microhomology to perform MMEJ. The polymerase activity is highly promiscuous: unlike most polymerases, promotes extension of ssDNA and partial ssDNA (pssDNA) substrates. Also exhibits low-fidelity DNA synthesis, translesion synthesis and lyase activity, and it is implicated in interstrand-cross-link repair, base excision repair and DNA end-joining (By similarity). Involved in somatic hypermutation of immunoglobulin genes, a process that requires the activity of DNA polymerases to ultimately introduce mutations at both A/T and C/G base pairs (PubMed:16222339, PubMed:16172387, PubMed:16890500, PubMed:17449470). However, POLQ does not play a major role in somatic hypermutation (PubMed:18485835). a 2'-deoxyribonucleoside 5'-triphosphate + DNA(n) = diphosphate + DNA(n+1) Homomultimer; forms dimers and multimers. Interacts with RAD51. Interacts with ORC2 and ORC4. Enriched in chromatin in response to ultaviolet (UV) light. Binds to chromatin during early G1. The loop 2 region is involved in the binding of the 2 ends of resected double-strand breaks and homomultimerization. Mice develop normally, but show elevated frequencies of spontaneous and radiation-induced micronuclei, due to an increased frequency of chromosomal breakage (PubMed:12663541, PubMed:15542845, PubMed:19630521). Mice display a 20% reduction of both A/T and C/G mutations during somatic hypermutation of immunoglobulin genes (PubMed:17449470). Mice lacking both Polh and Polq do not show a further decrease of A/T mutations as compared with mice lacking only Polh (PubMed:17449470). Mice lacking both Fancd2 and Polq die during embryogenesis (PubMed:25642960). Belongs to the DNA polymerase type-A family.