Research project
Understanding plant transgenesis
How is Pol θ responsible for T-DNA integration, and how do other DNA double-strand break repair pathways interact with Pol θ? How may we manipulate T-DNA integration to stimulate error-free integration at a predetermined genomic site?
- Duration
- 2017 - 2020
- Contact
- Marcel Tijsterman
- Funding
-
NWO
- Partners
Leiden University Medical Center (LUMC), Genome stability group
![](/binaries/content/gallery/ul2/main-images/unsorted/agrobacterium-tumefaciens.jpg/agrobacterium-tumefaciens.jpg/d300xvar)
Unravelling the molecular mechanisms that underlie plant genetic modification.
In nature, Agrobacterium tumefaciens genetically modifies plants by inserting T-DNA, containing tumor-inducing genes, into their genomes, causing crown gall disease. In the laboratory, tumor-inducing genes can be replaced by any desired sequence, making genetic transformation by Agrobacterium the most popular tool to create genetically modified plants.
![T-DNA integration in Arabidopsis roots: wild type Arabidopsis roots have successfully integrated T-DNA into their genome, while teb-5 Polymerase θ-deficient plants are unable to integrate T-DNA into their genome](/binaries/medium/content/gallery/ul2/images-in-text/science/ibl/kregten-1-2.png)
In 2016, we discovered, in collaboration with the Genome Stability Group at the LUMC, that T-DNA integration requires Polymerase Theta (Pol θ). DNA double-strand break repair by Pol θ captures T-DNA into genomic breaks. Random integration events, which constitute almost all events, are created by Pol θ. Random integration of T-DNA heavily impacts the function of integrated T-DNA, and impacts the genomic environment. Therefore, it represents a safety risk in genetically modified plants.
![](/binaries/large/content/gallery/ul2/images-in-text/science/ibl/kregten-2-2.png)
Current work aims to unravel the context in which Pol θ operates in T-DNA integration. We study interactions between Pol θ and other double-strand break repair pathways and their effects on the frequency of T-DNA integration, the molecular outcome of integration events, and explore possibilities to steer the T-DNA integration process towards error-free gene targeting.
- Van Kregten et al., T-DNA integration in plants results from polymerase-θ-mediated DNA repair, Nat. Plants, 2016