The Lost Epigenetic Mark: Uncovering the Function and Fate of 6mA in Eukaryotic Evolution

The study of cytosine methylation has revealed its critical roles in gene regulation and genome stability across plants and animals. In contrast, the functions of 6-methyladenine (6mA) remain largely mysterious, mostly because traditional model systems show very low levels or an absence of this mark. Our recent findings indicate that 6mA was ancestral in eukaryotes, with conserved genome-wide patterns found in diverse unicellular species that diverged over a billion years ago, including many human parasites. This project aims to illuminate the function of 6mA across various systems and explain its loss in multicellular organisms.To achieve this, we will leverage the advanced genetic tools available in the model amoeba Acanthamoeba castellanii to evaluate the potential roles of 6mA using gene disruption and functional genomics. Next, we will catalogue the diversity of 6mA “reader” proteins across a wide range of distantly related eukaryotes. Finally, we will reconstruct the ancestral 6mA pathway in mammalian cells to assess its compatibility with the complex epigenomes of multicellular organisms. By revealing the roles of 6mA, our research will reshape our understanding of genome regulation and epigenetics, potentially opening new avenues for drug development against parasitic protozoans and advancing synthetic biology through novel cellular memory tools.