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The Gene-Deletor Technology
The Yi Li laboratory at the University of Connecticut has developed a highly efficient ‘gene-deletor’ technology to delete all functional GM genes (transgenes) from pollen, seed or both.
Because of a novel use of the LoxP/Cre and FRT/Flp DNA recombination systems, the technology is 100% efficient to delete all functional GM genes based on more than 25,000 T1 progeny examined per transgenic event.
The ‘gene-deletor’ technology can be extended to destroy all functional GM genes from any parts of plants, particularly edible parts like fruits, tubers, flowers, grains or leaves.
The technology should be useful to address the gene flow problems and also to alleviate the safety concerns over GM foods.
Dr. Li’s group at UConn started the gene-deletor project in 2000 with funding from Connecticut Innovation Inc (CII), then from the Consortium for Plant Biotechnology Research / U.S. Department of Energy (CPBR/DOE) and UConn. The Li's team and collaborators in China and at the University of Tennessee, reported the gene deletor system in 2007.
The technology can be used to produce non-GM parts from GM plants:
-- When a pollen- and/or seed-specific gene promoter is used to control the Flp gene expression, all functional GM genes are deleted specifically from pollen and/or seed.
-- If a fruit-specific gene promoter is used to control the Flp gene expression, all functional GM genes should be deleted specifically from the fruit.
-- If a tuber-specific gene promoter is used to control the Flp gene expression, all functional GM genes should be deleted specifically from the tuber.
-- If a conditionally active, either developmental (e.g., post-harvesting active) or inducible (e.g., high- or low- temperature inducible or ethanol-inducible) gene promoter is used to control the Flp gene expression in all organs and tissues, all functional GM genes should be deleted from the entire plant.
Schematic illustration of the production of non-GM organs or a non-GM plant from a GM plant using the ‘gene-deletor’ technology. FLP is an enzyme that recognizes loxP-FRT sequence and acts as a scissor to delete all GM genes within the two loxP-FRT sequences. Several days after the deletion, the GM genes and their protein products will be destroyed.
The left panel shows that the 'gene-deletor" technology can be used to produce: A) non-GM pollen and non-GM seed from GM plants to address the pollen-and seed-mediated gene flow problem; B) and C) non-GM edible parts or non-GM plants from GM plants to address the safety concern over food produced from GM crops.
The right panel shows how the ‘gene-deletor" works to produce non-GM organs from GM plants: All GM genes, such as trait genes, selection marker gene and DNA recombinase (Flp) gene are inserted between the two loxP-FRT sites (86-bp in length). If the Flp gene is under the control of a pollen- and seed-specific gene promoter, all GM genes will be deleted from pollen and seeds. If a flower- and fruit-specific gene promoter is used to control the Flp expression, all functional GM genes will be deleted from flowers and fruits. If a conditionally inducible, such as a chemically inducible or high-temperature inducible, gene promoter is used to control the Flp expression, all functional GM genes should be deleted throughout the plant upon application of the inducer. |
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