DNA polymerase beta can incorporate ribonucleotides during DNA synthesis of undamaged and CPD-damaged DNA

Overexpression of the error-prone DNA polymerase beta (Pol beta) has been found to increase spontaneous mutagenesis by competing with the replicative polymerases during DNA replication. Here, we investigate an additional mechanism potentially used by Pol beta to enhance genetic instability via its a...

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Bibliographic Details
Published in:Journal of molecular biology 2003-08, Vol.331 (5), p.1017-1023
Main Authors: Bergoglio, Valérie, Ferrari, Elena, Hübscher, Ulrich, Cazaux, Christophe, Hoffmann, Jean Sébastien
Format: Article
Language:English
Subjects:
Animals
Base Sequence
Cattle
DNA - biosynthesis
DNA - chemistry
DNA - genetics
DNA Adducts - biosynthesis
DNA Damage
DNA Polymerase beta - metabolism
DNA Replication
Humans
In Vitro Techniques
Molecular Sequence Data
Mutagenesis
Pyrimidine Dimers - metabolism
Ribonucleotides - metabolism
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Summary:Overexpression of the error-prone DNA polymerase beta (Pol beta) has been found to increase spontaneous mutagenesis by competing with the replicative polymerases during DNA replication. Here, we investigate an additional mechanism potentially used by Pol beta to enhance genetic instability via its ability to incorporate ribonucleotides into DNA. By using an in vitro primer extension assay, we show that purified human and calf thymus Pol beta can synthesize up to 8-mer long RNA. Moreover, Pol beta can efficiently incorporate rCTP opposite G in the absence of dCTP and, to a lesser extent, rATP opposite T in the absence of dATP and rGTP opposite C in the absence of dGTP. Recently, Pol beta was shown to catalyze in vitro translesion replication of a thymine cyclobutane pyrimidine dimer (CPD). Here, we investigate if ribonucleotides could be incorporated opposite the CPD damage and modulate the efficiency of the bypass process. We find that all four rNTPs can be incorporated opposite the CPD lesion, and that this process affects translesion synthesis. We discuss how incorporation of ribonucleotides into DNA may contribute to the high frequency of mutagenesis observed in Pol beta up-regulating cells.
ISSN:0022-2836
DOI:10.1016/S0022-2836(03)00837-4