摘要 |
<p>The invention is based on the discovery that recombinagenic oligonucleobases are active in prokaryotic cells that contain a strand transfer activity (RecA) and mismatch repair activity (MutS). Using this system a type of Duplex Mutational Vector termed a Heteroduplex Mutational Vector, was shown to be more active in prokaryotic cells than the types of mutational vectors heretofore tested. Further improvements in activity were obtained by replacing the tetrathymidine linker by a nuclease resistant oligonucleotide, such as tetra-2'-O-methyl-uridine, to link the two strands of the recombinagenic oligonucleobase and removing the DNA-containing intervening segment. The claims concern Duplex Mutational Vectors that contain the above improvements. In an alternative embodiment the claims concern the use of Duplex Mutational Vectors in prokaryotic cells.</p> |