Sall, S. O. | Search bioRxiv

bioRxiv2026

The INO80-EEN complex prevents genomic rearrangements at protein coding genes regions

Plants are continuously exposed to a myriad of DNA-damaging agents, including environmental cues such as sunlight. At the cellular level, plants respond to DNA damage by activating DNA damage response (DDR) pathways, in which chromatin remodelers play an important role. Among them, the evolutionary conserved INO80 complex (INO80c) has been shown in Arabidopsis to play a key role in DDR, notably by positively regulating Homologous Recombination (HR). Arabidopsis EIN6 ENHANCER (EEN) is the homolog of Yeast INO EIGHTY SUBUNIT 6 and interacts with the N-terminal region of INO80 in the INO80c. Using plant phenotyping, cellular and molecular biology, and third-generation sequencing technology we investigated how INO80 and EEN regulate plant development and genome integrity. We uncovered new roles for INO80 and EEN in plant growth and for INO80 in fine tuning endoreduplication. In addition, linear genome analysis revealed an important and unexpected function for the INO80-EEN complex in preventing Protein Coding Genes (PCGs) from structural rearrangements in somatic tissue and upon exposure to UV-B. Therefore, our results shed new light on the previously overlooked roles of INO80 and EEN in protecting genome integrity at PCGs.

plant biology↗

bioRxiv2024

Characterization of radiations-inducedgenomic structural variations in Arabidopsis thaliana

DNA, is assaulted by endogenous and exogenous agents that lead to the formation of damage. In order to maintain genome integrity DNA repair pathways must be efficiently activated to prevent mutations and deleterious chromosomal rearrangements. Conversely, genome flexibility is also necessary to allow genetic diversity and evolution. The antagonist interaction between maintenance of genome integrity and flexibility determines genome shape and organization. Therefore, it is of great interest to understand how the whole linear genome structure behaves upon formation and repair of DNA damage. For this, we used long reads sequencing technology to identify and to characterize genomic structural variations (SV) of wild-type Arabidopsis thaliana somatic cells exposed either to UV-B, to UV-C or to protons irradiations. We found that genomic regions located in heterochromatin a more prone to form SVs than those located in euchromatin, highlighting that genome stability and flexibility differs along the chromosome. This holds true in Arabidopsis plants deficient for the expression of master regulators of the DNA Damage Response (DDR), ATM and ATR, suggesting that independent and alternative surveillance processes exist to maintain integrity in genic regions. Finally, the analysis of the radiations-induced deleted regions allowed determining that exposure UV-B, UV-C and protons induced the Microhomology-mediated end joining mechanism (MMEJ) and that both ATM and ATR repress this repair pathway.

plant biology↗