DNA primase and DNA polymerase required to tolerate replication-stalling lesions by bypassing them (PubMed:24126761, PubMed:24207056, PubMed:24240614, PubMed:24267451, PubMed:24682820, PubMed:25255211, PubMed:25262353, PubMed:25550423, PubMed:25746449, PubMed:27989484, PubMed:28534480, PubMed:29608762, PubMed:30889508, PubMed:31676232). Required to facilitate mitochondrial and nuclear replication fork progression by initiating de novo DNA synthesis using dNTPs and acting as an error-prone DNA polymerase able to bypass certain DNA lesions (PubMed:24126761, PubMed:24207056, PubMed:24240614, PubMed:24267451, PubMed:24682820, PubMed:25255211, PubMed:25262353, PubMed:25550423, PubMed:25746449, PubMed:27989484, PubMed:28534480, PubMed:29608762, PubMed:30633872, PubMed:30889508). Shows a high capacity to tolerate DNA damage lesions such as 8oxoG and abasic sites in DNA (PubMed:24126761, PubMed:24207056, PubMed:24240614, PubMed:24267451, PubMed:25746449). Provides different translesion synthesis alternatives when DNA replication is stalled: able to synthesize DNA primers downstream of lesions, such as ultraviolet (UV) lesions, R-loops and G-quadruplexes, to allow DNA replication to continue (PubMed:24240614, PubMed:26626482, PubMed:28534480, PubMed:30478192). Can also realign primers ahead of 'unreadable lesions' such as abasic sites and 6-4 photoproduct (6-4 pyrimidine- pyrimidinone), thereby skipping the lesion. Repriming avoids fork degradation while leading to accumulation of internal ssDNA gaps behind the forks (PubMed:24240614, PubMed:25746449, PubMed:31676232). Also able to incorporate nucleotides opposite DNA lesions such as 8oxoG, like a regular translesion synthesis DNA polymerase (PubMed:24207056, PubMed:25255211, PubMed:25746449). Also required for reinitiating stalled forks after UV damage during nuclear DNA replication (PubMed:24240614). Required for mitochondrial DNA (mtDNA) synthesis and replication, by reinitiating synthesis after UV damage or in the presence of chain-terminating nucleotides (PubMed:24207056). Prevents APOBEC family-mediated DNA mutagenesis by repriming downstream of abasic site to prohibit error-prone translesion synthesis (By similarity). Has non-overlapping function with POLH (PubMed:24240614). In addition to its role in DNA damage response, also required to maintain efficient nuclear and mitochondrial DNA replication in unperturbed cells (PubMed:30715459). {ECO:0000250|UniProtKB:Q6P1E7, ECO:0000269|PubMed:24126761, ECO:0000269|PubMed:24207056, ECO:0000269|PubMed:24240614, ECO:0000269|PubMed:24267451, ECO:0000269|PubMed:24682820, ECO:0000269|PubMed:25255211, ECO:0000269|PubMed:25262353, ECO:0000269|PubMed:25550423, ECO:0000269|PubMed:25746449, ECO:0000269|PubMed:26626482, ECO:0000269|PubMed:27989484, ECO:0000269|PubMed:28534480, ECO:0000269|PubMed:29608762, ECO:0000269|PubMed:30478192, ECO:0000269|PubMed:30633872, ECO:0000269|PubMed:30715459, ECO:0000269|PubMed:30889508, ECO:0000269|PubMed:31676232}. This is the function of ENSG00000164306 (PRIMPOL, primase and DNA directed polymerase).