Arabidopsis methylation elevated mutant 1(mem1)mutants have elevated levels of global DNA methylation. In this study, such mutant alleles showed increased sensitivity to methyl methanesulfonate(MMS). In mem1 mutants, ...Arabidopsis methylation elevated mutant 1(mem1)mutants have elevated levels of global DNA methylation. In this study, such mutant alleles showed increased sensitivity to methyl methanesulfonate(MMS). In mem1 mutants, an assortment of genes engaged in DNA damage response(DDR), especially DNA-repair-associated genes, were largely upregulated without MMS treatment, suggestive of activation of the DDR pathway in them. Following MMS treatment, expression levels of multiple DNArepair-associated genes in mem1 mutants were generally lower than in Col-0 plants, whichaccounted for the MMS-sensitive phenotype of the mem1 mutants. A group of DNA methylation pathway genes were upregulated in mem1 mutants under non-MMS-treated conditions, causing elevated global DNA methylation, especially in RNAdirected DNA methylation(Rd DM)-targeted regions.Moreover, MEM1 seemed to help ATAXIATELANGIECTASIA MUTATED(ATM) and/or SUPPRESSOR OF GAMMA RESPONSE 1(SOG1) to fully activate/suppress transcription of a subset of genes regulated simultaneously by MEM1 and ATM and/or SOG1, because expression of such genes decreased/increased consistently in mem1 and atm and/or sog1 mutants, but the decreases/increases in the mem1 mutants were not as dramatic as in the atm and/or sog1 mutants. Thus, our studies reveals roles of MEM1 in safeguarding genome, and interrelationships among DNA damage, activation of DDR, DNA methylation/demethylation, and DNA repair.展开更多
基金supported by the National Natural Science Foundation of China(31771427,31970582 to H.L.)supported by the high-performance computing platform of Bioinformatics Center,Nanjing Agricultural University。
文摘Arabidopsis methylation elevated mutant 1(mem1)mutants have elevated levels of global DNA methylation. In this study, such mutant alleles showed increased sensitivity to methyl methanesulfonate(MMS). In mem1 mutants, an assortment of genes engaged in DNA damage response(DDR), especially DNA-repair-associated genes, were largely upregulated without MMS treatment, suggestive of activation of the DDR pathway in them. Following MMS treatment, expression levels of multiple DNArepair-associated genes in mem1 mutants were generally lower than in Col-0 plants, whichaccounted for the MMS-sensitive phenotype of the mem1 mutants. A group of DNA methylation pathway genes were upregulated in mem1 mutants under non-MMS-treated conditions, causing elevated global DNA methylation, especially in RNAdirected DNA methylation(Rd DM)-targeted regions.Moreover, MEM1 seemed to help ATAXIATELANGIECTASIA MUTATED(ATM) and/or SUPPRESSOR OF GAMMA RESPONSE 1(SOG1) to fully activate/suppress transcription of a subset of genes regulated simultaneously by MEM1 and ATM and/or SOG1, because expression of such genes decreased/increased consistently in mem1 and atm and/or sog1 mutants, but the decreases/increases in the mem1 mutants were not as dramatic as in the atm and/or sog1 mutants. Thus, our studies reveals roles of MEM1 in safeguarding genome, and interrelationships among DNA damage, activation of DDR, DNA methylation/demethylation, and DNA repair.
