Human Pol ζ purified with accessory subunits is active in translesion DNA synthesis and complements Pol η in cisplatin bypass

• DOI: 10.1073/pnas.1324001111
• Publication Date: 2014-01-22T04:02:30Z
• Authors: Young-Sam Lee; Mark T. Gregory; Wei Yang
• Keywords: Processivity

DNA polymerase ζ (Pol ζ) is a eukaryotic B-family that specializes in translesion synthesis and essential for normal embryogenesis. At minimum, Pol consists of catalytic subunit Rev3 an accessory Rev7. Mammalian contains >3,000 residues twice as large the yeast homolog. To date, no vertebrate has been purified biochemical characterization. Here we report purification series human deletion constructs expressed HEK293 cells identification minimally catalytically active variant. With tagged form variant, isolated two additional subunits ζ, PolD2 PolD3. The four-subunit ζ4 (Rev3-Rev7-PolD2-PolD3) much more efficient processive at bypassing 1,2-intrastrand d(GpG)-cisplatin cross-link than two-subunit ζ2 (Rev3-Rev7). We show complete bypass cisplatin lesions requires η to insert dCTP opposite 3' guanine extend primers.