| 研究実績の概要 |
Iron is assembled inside cells into cofactors, essential for biological functions. Two types of cofactors, iron sulfur clusters and diferric tyrosyl radicals, share a conserved assembly complex containing the DRE2 enzyme, essential for cell viability in eukaryotes. In the model plant Arabidopsis thaliana, dre2 mutants are lethal, having a maternal defect related to active DNA demethylation in the central cell gamete. In addition, dre2 mutants have a zygotic defect leading to embryo arrest. However, neither of these defects is fully penetrant.Homozygote mutants were recovered using complementation with a promoter specific to the central cell maternal gamete. This allowed the characterisation of a range of novel molecular and phenotypic abnormalities associated with lack of DRE2 function. Surprisingly, dre2 mutants have additional reproductive phenotypes. Also, DNA methylation defects at three genes normally targeted by DNA glycosilases for DNA demethylation were found in vegetative cells. This suggests that DRE2 has a function in DNA demethylation in vegetative as well as reproductive phase.
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