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Cre-Lox Site-Specific Recombination Between Arabidopsis And Tobacco Chromosomes

Ow, David
Heather - USDA PGEC
Submitted to: Plant Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 1, 2000
Publication Date: September 1, 2000

Interpretive Summary: This work tested the possibility of recombining chromosomes from different plant species through site-specific recombination. Transgenic tobacco and Arabidopsis lines harboring recombination sites were fused to bring the two genomes into the same hybrid cell. Site-specific recombination between tobacco and Arabidopsis chromosomes leading to chromosome translocation was observed. Two recombinant lines were characterized showing large segments of Arabidopsis DNA transferred to the tobacco chromosome. Regenerated plants, however, did not maintain the chimeric chromosomes.
Technical Abstract: To create hybrid chromosomes, we tested the Cre-lox system to mediate recombination between Arabidopsis thaliana and Nicotiana Tabacum chromosomes. Protoplasts of the two plants were fused to allow site-specific recombination to join a promoter from tobacco to a hygromycin resistance coding-region from Arabidopsis. The expected recombination junction was detected in hygromycin-resistant calli. Analysis of one hybrid suspension cell-line revealed the presence of markers corresponding to the north arm of Arabidopsis chromosome III, but not markers from other chromosome arms. However, these markers were not detected in regenerated plants. With a second Hybrid cell line, we obtained a single hygromycin-resistant progeny from ~18,000 self-fertilized seeds of one regenerated plant. Molecular analysis of this hybrid indicated that a small portion of the north arm of Arabidopsis chromosome V is present in the tobacco genome. However, neither the recombination junction nor Arabidopsis DNA was detected in tissue from the plant grown without selection, or in the subsequent generation. Thus, interspecies transfer of a chromosome arm between plant cells is possible but maintenance of the hybrid chromosome in a plant is unlikely. The feasibility of site-specific recombination between genomes of different species offers new possibilities for engineering hybrid chromosomes that may be maintained in cell culture.