DNA polymerase ζ: new insight into eukaryotic mutagenesis and mammalian embryonic development

Figure 1 TLS two-step model in human cells. (1) The main replicase in humans, pol δ, has difficulty in replicating through cis-syn T-T cyclobutane dimmer and (6-4) T-T photoproduct. This recruits specialized polymerases such as pol η, pol ι to insert or misinsert deoxynucleotides, and then pol ζ functions as a mismatch extender. (2) Opposite the abasic site, pol ιor REV1 inserts a deoxynucleotide, and bypass of this lesion occurs when combined with pol ζ.