Abstract
Little is known about the translesion synthesis (TLS) in higher plants. We have isolated and characterized an Arabidopsis homolog (AtREV1) of the yeast REV1 gene that is involved in the error-prone TLS. An AtREV1-disrupted mutant was sensitive to UV-B and DNA crosslinking-agents, suggesting that the error-prone TLS is important for tolerance to DNA damages. To clarify the functions of AtREV1 in error-prone TLS, we overexpressed the AtREV1 in E. coli and purified the recombinant protein by affinity-column and anion-exchange column chromatographies. The activity of the purified AtREV1 was analyzed by primer extension assay using four kinds of oligonucleotides annealed with a 32P-labelled primer. As a result, the AtREV1 efficiently transferred a dCMP opposite guanine, adenine, thymine and cytosine. In addition, AtREV1 inserted a dTMP opposite guanine with a similar efficiency to transfer dCMP. These results demonstrate that AtREV1 is a member of low-fidelity DNA polymerases with a deoxycytidyl transferase activity.
