DNA Methylation on N6-Adenine Regulates the Hyphal Development during Dimorphism in the Early-Diverging Fungus .

The epigenetic modifications control the pathogenicity of human pathogenic fungi, which have been poorly studied in Mucorales, causative agents of mucormycosis. This order belongs to a group referred to as early-diverging fungi that are characterized by high levels of N6-methyldeoxy adenine (6mA) in their genome with dense 6mA clusters associated with actively expressed genes. AlkB enzymes can act as demethylases of 6mA in DNA, with the most remarkable eukaryotic examples being mammalian ALKBH1 and NMAD-1. The (formerly f. ) genome contains one gene, , and two genes, and , encoding proteins similar to NMAD-1 and ALKBH1, respectively. The function of these three genes was analyzed by the generation of single and double deletion mutants for each gene. Multiple processes were studied in the mutants, but defects were only found in single and double deletion mutants for . In contrast to the wild-type strain, mutants showed an increase in 6mA levels during the dimorphic transition, suggesting that 6mA is associated with dimorphism in . Furthermore, the spores of mutants challenged with macrophages underwent a reduction in polar growth, suggesting that 6mA also has a role during the spore-macrophage interaction that could be important in the infection process.