Open AccessEndonuclease-induced, targeted homologous extrachromosomal recombination in Xenopus oocytes.
Author(s) -
David J. Segal,
Dana Carroll
Publication year - 1995
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.92.3.806
Subject(s) - homologous recombination , extrachromosomal dna , flp frt recombination , recombination , in vitro recombination , xenopus , biology , dna , plasmid , non homologous end joining , endonuclease , microbiology and biotechnology , gene targeting , d loop , genetics , site specific recombination , homologous chromosome , genetic recombination , non allelic homologous recombination , gene , mitochondrial dna , molecular cloning , complementary dna , recombinase
Homologous recombination in gene targeting in most organisms occurs by an inefficient mechanism. Inducing a double-strand break in the chromosomal target may increase this efficiency by allowing recombination to proceed by the highly efficient single-strand annealing mechanism. A gene targeting experiment was modeled in Xenopus oocytes by using a circular plasmid to mimic the chromosomal target site and a homologous linear molecule (pick-up fragment or PUF) as an analogue of the vector DNA. When those two molecules were simply injected together, no recombination was observed. In contrast, when the circular plasmid was cleaved in vivo by injection of the site-specific endonuclease, I-Sce I, relatively efficient intermolecular recombination occurred, involving up to 17% of the cleaved molecules. Recombination was dependent on the stability of the PUF; product yield was increased by using longer fragments and by injecting larger amounts of linear DNA, both of which increased the lifetime of the PUF in the oocytes. These results demonstrate that in vivo double-strand breaks can induce homologous recombination of reluctant substrates and may be useful in augmenting the efficiency of gene targeting.