Translesion DNA synthesis by yeast DNA polymerase eta on templates containing N-2-guanine adducts of 1,3-butadiene metabolites

Yeast DNA polymerase eta can replicate through cis-syn cyclobutane pyrimidi ne dimers and 8-oxoguanine lesions with the same efficiency and accuracy as replication of an undamaged template. Previously, it has been shown that E scherichia coli DNA polymerases I, II, and III are incapable of bypassing D NA substrates containing N-2-guanine adducts of stereoisomeric 1,3-butadien e metabolites. Here we showed that yeast polymerase eta replicates DNA cont aining the monoadducts (S)-butadiene monoepoxide and (S,S)-butadiene diolep oxide N-2-guanines albeit at an similar to 200-300-fold lower efficiency re lative to the control guanine, Interestingly, nucleotide incorporation oppo site the (R)-butadiene monoepoxide and the (R,R)-butadiene diolepoxide N-2- guanines was similar to 10-fold less efficient than incorporation opposite their S stereoisomers, Polymerase eta preferentially incorporates the corre ct nucleotide opposite and downstream of all four adducts, except that it s hows high misincorporation frequencies for elongation of C paired with (R)b utadiene monoepoxide N-2-guanine. Additionally, polymerase eta does not byp ass the (R,R)- and (S,S)butadiene diolepoxide N-2-guanine-N-2-guanine intra strand cross-links, and replication is completely blocked just prior to the lesion. Collectively, these data suggest that polymerase eta can tolerate the geometric distortions in DNA conferred by the N-2-guanine butadiene mon oadducts but not the intrastrand cross-links.