Uracil within DNA: an actor of antiviral immunity

Joséphine Sire¹ , Gilles Quérat¹ , Cécile Esnault² and Stéphane Priet³

¹UMR IRD-190, Emergence des Pathologies Virales, Faculté de Médecine, 27 Bd Jean Moulin, 13005 Marseille, France

²Unité des Rétrovirus Endogènes et Eléments Rétroïdes des Eucaryotes Supérieurs, UMR 8122 CNRS, Institut Gustave Roussy, 94805 Villejuif, France

³Architecture et Fonction des Macromolécules Biologiques, CNRS UMR 6098, ESIL case 925, 13288 Marseille Cedex 9, France

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Retrovirology 2008, 5:45doi:10.1186/1742-4690-5-45


Published:	5 June 2008

Abstract

Uracil is a natural base of RNA but may appear in DNA through two different pathways including cytosine deamination or misincorporation of deoxyuridine 5'-triphosphate nucleotide (dUTP) during DNA replication and constitutes one of the most frequent DNA lesions. In cellular organisms, such lesions are faithfully cleared out through several universal DNA repair mechanisms, thus preventing genome injury. However, several recent studies have brought some pieces of evidence that introduction of uracil bases in viral genomic DNA intermediates during genome replication might be a way of innate immune defence against some viruses. As part of countermeasures, numerous viruses have developed powerful strategies to prevent emergence of uracilated viral genomes and/or to eliminate uracils already incorporated into DNA. This review will present the current knowledge about the cellular and viral countermeasures against uracils in DNA and the implications of these uracils as weapons against viruses.