Open AccessGene conversion in transgenic maize plants expressing FLP/ FRT and Cre/ loxP site‐specific recombination systems
Author(s) -
Djukanovic Vesna,
Orczyk Waclaw,
Gao Huirong,
Sun Xifan,
Garrett Nicole,
Zhen Shifu,
GordonKamm William,
Barton Joanne,
Lyznik L. Alexander
Publication year - 2006
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1111/j.1467-7652.2006.00186.x
Subject(s) - homologous recombination , site specific recombination , flp frt recombination , biology , mitotic crossover , recombination , genetics , cre lox recombination , zygote , ectopic recombination , gene , gene targeting , recombinase , transgene , non homologous end joining , in vitro recombination , genetic recombination , gene conversion , genetically modified mouse , molecular cloning , gene expression , embryogenesis
Summary DNA recombination reactions (site‐specific and homologous) were monitored in the progeny of transgenic maize plants by bringing together two recombination substrates (docking sites and shuttle vectors) in the zygotes. In one combination of transgenic events, the recombination marker gene (yellow fluorescent protein gene, YFP ) was activated in 1%−2% of the zygotes receiving both substrates. In other crosses, chimeric embryos and plants were identified, indicative of late recombination events taking place after the first mitotic division of the zygotes. The docking site structure remained unchanged; therefore, all recovered recombination events were classified as gene conversions. The recombinant YFP‐r gene segregated as a single locus in subsequent generations. The recombination products showed evidence of homologous recombination at the 5′ end of the YFP marker gene and recombinational rearrangements at the other end, consistent with the conclusion that DNA replication was involved in generation of the recombination products. Here, we demonstrate that maize zygotes are efficient at generating homologous recombination products and that the homologous recombination pathways may successfully compete with other possible DNA repair/recombination mechanisms such as site‐specific recombination. These results indicate that maize zygotes provide a permissive environment for homologous recombination, offering a new strategy for gene targeting in maize.