Biochemical characterization of rec1 mutants and the genetic control of recombination in Ustilago maydis.
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Alleles↗
Biomedical subjects
E B Kmiec
Publications and source records attributed to E B Kmiec.
Heteroduplex formation and polarity during strand transfer promoted by Ustilago rec 1 protein.
Ustilago rec1 protein promotes formation of joint molecules between circular strands and linear duplex DNA in two stages. During the first stage--synapsis--ATP, or the nonhydrolyzable analog adenylyl-imidodiphosphate, is a necessary cofactor in the formation of complexes. During the second stage--strand exchange--transfer of the circular single strand to the duplex appears to require energy derived from ATP hydrolysis. Rec1-promoted strand exchange is driven in a unique direction. Circular plus strand pairs with the 5' end of its complement in the linear duplex molecule. The 3' end of the plus strand is displaced from the duplex as the circle rolls in.
Adenosine Triphosphate↗
Topological linkage of circular DNA molecules promoted by Ustilago rec 1 protein and topoisomerase.
We studied the formation of linked circular DNA molecules promoted by the combined action of rec 1 protein and type I topoisomerase of Ustilago maydis. When ATP was added as cofactor to reactions containing rec 1 protein, pairs of homologous circular DNA molecules became linked after addition of topoisomerase. Closed circular duplex molecules could be joined at homologous sites with circular single-stranded molecules or with other circular duplex molecules, provided that homologous single-stranded DNA fragments or RNA polymerase and nucleoside triphosphates were also added. Complexes formed were topologically linked through regions of heteroduplex DNA. When the analog adenylyl-imidodiphosphate was substituted for ATP, nonhomologous pairs of circular DNA molecules became linked.
Adenosine Triphosphate↗
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.
Antigens, CD34↗