5 '-Deoxyribose phosphate lyase activity of human DNA polymerase iota in vitro

DNA polymerase iota (pol iota) is one of several recently discovered DNA po lymerases in mammalian cells whose function is unknown. We report here that human pol iota has an intrinsic 5'-deoxyribose phosphate (dRP) Lyase activ ity. In reactions reconstituted with uracil-DNA glycosylase (UDC), apurinic /apyrimidinic (AP) endonuclease and DNA Ligase I, pol iota can use its dRP Lyase and polymerase activities to repair G . U and A . U pairs in DNA, The se data and three distinct catalytic properties of pol iota implicate it in specialized forms of base excision repair (BER).