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bioRxiv · 10.1101/2022.04.08.487320

The multi-BRCT domain protein DDRM2 is required for homologous recombination in plants

Wang, L.·Yu, C.·Hou, L.·Huang, Y.·Cui, X.·Xu, S.·Yan, S.
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Abstract

DNA double-strand breaks (DSBs) are the most toxic DNA damage for cells. Homologous recombination (HR) is a precise DSB repair mechanism as well as a basis for gene targeting using genome-editing techniques. Despite the importance of HR, the HR mechanism in plants is poorly understood. In a genetic screen for DNA Damage Response Mutants (DDRMs), we find that the Arabidopsis ddrm2 mutant is hypersensitive to DSB-inducing reagents. DDRM2 encodes a protein with four BRCA1 C-terminal (BRCT) domains and is highly conserved in plants including the earliest land plant linage, bryophytes. The plant-specific transcription factor SOG1 binds to the promoter of DDRM2 and activates its expression, suggesting that DDRM2 is a direct target of SOG1. In consistence, the expression of DDRM2 is induced by DSBs in a SOG1-dependent manner. Epistasis analysis indicates that DDRM2 functions downstream of SOG1. Similar to the sog1 mutant, the ddrm2 mutant shows dramatically reduced HR efficiency. Our study suggests that the SOG1-DDRM2 module is required for HR, providing new insights into the HR mechanisms in plants and a potential target for improving the efficiency of gene targeting. One Sentence SummaryA genetic screen in Arabidopsis reveals that the multi-BRCT domain protein DDRM2 is required for homologous recombination and is targeted by the master DNA damage response regulator SOG1.

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Wang, L., Yu, C., Hou, L., Huang, Y., Cui, X., Xu, S., Yan, S.. 2022-04-09. The multi-BRCT domain protein DDRM2 is required for homologous recombination in plants. https://doi.org/10.1101/2022.04.08.487320

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