Removal of 2′,3′-dideoxynucleotide residues from injected DNA in Xenopus laevis oocytes

Dideoxynucleotides have proved to be potent differential inhibitors of DNA polymerases in vitro and in vivo. Used extensively in studies of DNA repair and replication, they have more recently been used as antiviral agents particularly in treating patients for acquired immunodeficiency syndrome (AIDS). Once incorporated, these sugar-modified analogues prevent the further extension of the polynucleotide chain because of the absence of a 3′-hydroxyl group. We demonstrated that, upon injection into Xenopus laevis oocytes, 2′,3′-dideoxynucleotides are efficiently removed from plasmid DNA preterminated with these analogues allowing subsequent closure by ligation. The removal process is not sensitive to aphidicolin but is quantitatively inhibited by novobiocin.