Targeted gene conversion in a mammalian CD34(+)-enriched cell population using a chimeric RNA/DNA oligonucleotide

Gene conversion of genetically inherited point mutations is a fundamental methodology for treating a variety of diseases. We tested the feasibility of a new approach using an RNA/DNA chimeric oligonucleotide. The beta-globin gene was targeted at the point mutation causing sickle cell anemia. The chimera is designed to convert an A residue to a T after creating a mismatched basepair. In a CD34(+)-enriched population of normal cells a 5-11% conversion rate was measured using restriction enzyme polymorphism and direct DNA sequence analyses. The closely related delta-globin gene sequence appeared unchanged despite successful conversion at the beta-globin locus.