The Pol Mutagenesis Pathway in Eukaryotes

6b Rev3-Rev7 Complex Forms the Translesion Polymerase Pol . The 

Purified yeast Pol is able to perform limited nucleotide insertions opposite several DNA lesions such as TT (6-4) photoproduct, AAF-dG adduct, and (+) or ( )-trans-anti-BPDE-N2-dG adduct. Furthermore, Pol also catalyzes extension synthesis from opposite many types of lesions with varying efficiencies, including an AP site, cis-syn TT dimer, (64) photoproduct, AAF-dG adduct, (+) or (-)-trans-an//-BPDE-/V2-dG adduct, and an acrolein-derived dG adduct. Therefore, it has been proposed that Pol functions both as an insertion polymerase and an extension polymerase. It appears that the extension activity of Pol is versatile. Thus, it is believed that Pol is a major extension polymerase during translesion synthesis in eukaryotes. 

Opposite the 3 T of a TT dimer, Pol is unable to insert a nucleotide in vitro, although it is active for translesion synthesis opposite the 5 T of the dimer. Thus, other translesion polymerases are required to bypass the 3 T of the TT dimer and other lesions for which Pol is inactive. During translesion synthesis, the active site 

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