第1433回生物科学セミナー
Mechanisms and origins of targeted DNA repair in plants
Grey Monroe（University of California, Davis）
2022年12月23日(金) 10:30-12:00 理学部2号館講堂
Mutations provide the raw material of evolution. The rate of mutation, which has been longstanding interest to biologists, reflects the balance between DNA damage and repair. As a consequence, mechanisms that target DNA repair proteins to particular regions of the genome have consequences on intragenomic mutation rate variation. Our lab is studying mutation rate variation in plants, using mutation accumulation experiments, mutagenesis populations, and somatic mutation screening inspired by tools in cancer research. This work has revealed significant variation in mutation rates across plant genomes. Most strikingly, we consistently observe that regions marked by the H3K4me1 histone modification see a reduction in mutation rate. In plants, H3K4me1 marks gene bodies and essential genes, suggesting the evolution of mechanisms that regions where de novo mutations are most likely to be deleterious. Deeper investigation into DNA repair proteins reveals multiple that contain Tudor histone reader domains which evidence of H3K4me1 binding specificity. These discoveries provide a mechanistic basis for targeted DNA repair in plants that parallel similar pathways in humans. They reveal a case of convergent evolution in which plants and animals, lineages with over 2 billion years of evolutionary divergence, have evolved independent but functionally analogous mechanisms to protect their most important genome regions from mutation.
参考文献
Monroe, JG., et al. (2022) Mutation bias reflects natural selection in Arabidopsis thaliana. Nature 602. 101-105.
Quiroz, D…. Monroe, JG. (2022). The H3K4me1 histone mark recruits DNA repair to functionally constrained genomic regions in plants. bioRxiv.
Monroe, JG. (2022) Potential and limits of (mal) adaptive mutation rate plasticity in plants. New Phytologist. doi: 10.1111/nph.18640. (online.)
担当： 東京大学大学院理学系研究科・生物科学専攻・遺伝学研究室
