N6-Methyladenine DNA Modification in Drosophila

• 6mA modification occurs in fly embryo DNA and is regulated by DMAD
• DMAD promotes differentiation of early germ cells in fly ovary
• DMAD catalyzes demethylation of 6mA both in vivo and in vitro
• DMAD-mediated 6mA demethylation is correlated with transposon expression

SummaryDNA N6-methyladenine (6mA) modification is commonly found in microbial genomes and plays important functions in regulating numerous biological processes in bacteria. However, whether 6mA occurs and what its potential roles are in higher-eukaryote cells remain unknown. Here, we show that 6mA is present in Drosophila genome and that the 6mA modification is dynamic and is regulated by the Drosophila Tet homolog, DNA 6mA demethylase (DMAD), during embryogenesis. Importantly, our biochemical assays demonstrate that DMAD directly catalyzes 6mA demethylation in vitro. Further genetic and sequencing analyses reveal that DMAD is essential for development and that DMAD removes 6mA primarily from transposon regions, which correlates with transposon suppression in Drosophila ovary. Collectively, we uncover a DNA modification in Drosophila and describe a potential role of the DMAD-6mA regulatory axis in controlling development in higher eukaryotes.

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