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Involvement of KU80 in T-DNA integration in plant cells.

Abstract : In Agrobacterium-mediated genetic transformation of plant cells, the bacterium exports a well defined transferred DNA (T-DNA) fragment and a series of virulence proteins into the host cell. Following its nuclear import, the single-stranded T-DNA is stripped of its escorting proteins, most likely converts to a double-stranded (ds) form, and integrates into the host genome. Little is known about the precise mechanism of T-DNA integration in plants, and no plant proteins specifically associated to T-DNA have been identified. Here we report the direct involvement of KU80, a protein that binds dsT-DNA intermediates. We show that ku80-mutant Arabidopsis plants are defective in T-DNA integration in somatic cells, whereas KU80-overexpressing plants exhibit increased susceptibility to Agrobacterium infection and increased resistance to DNA-damaging agents. The direct interaction between dsT-DNA molecules and KU80 in planta was confirmed by immunoprecipitation of KU80 dsT-DNA complexes from Agrobacterium-infected plants. Transformation of KU80-overexpressing plants with two separate T-DNA molecules resulted in an increased rate of extrachromosomal T-DNA to T-DNA recombination, indicating that KU80 bridges between dsT-DNAs and double-strand breaks. This last result further supports the notion that integration of T-DNA molecules occurs through ds intermediates and requires active participation of the host's nonhomologous end-joining repair machinery.
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Contributor : Charles White <>
Submitted on : Wednesday, May 25, 2011 - 11:30:01 PM
Last modification on : Wednesday, March 4, 2020 - 11:26:39 AM

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Jianxiong Li, Manjusha Vaidya, Charles White, Alexander Vainstein, Vitaly Citovsky, et al.. Involvement of KU80 in T-DNA integration in plant cells.. Proceedings of the National Academy of Sciences of the United States of America , National Academy of Sciences, 2005, 102 (52), pp.19231-6. ⟨10.1073/pnas.0506437103⟩. ⟨inserm-00595925⟩



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