Functions of human DNA polymerases η, κ and ι suggested by their properties, including fidelity with undamaged DNA templates

Human DNA polymerases η, κ and ι are template-dependent, Y-family DNA polymerases that have been implicated in translesion DNA synthesis (TLS) in human cells. Here, we briefly review evidence that these exonuclease-deficient polymerases copy undamaged DNA with very low fidelity and unusual error specificity. Based on the base substitution specificity and other biochemical properties of DNA polymerases η and ι, we consider the possibility that they participate in specialized DNA transactions that repair damaged DNA and/or generate mutations in the variable regions of immunoglobulin genes.