Papel de la metilación de adeninas del ADN en la regulación de la transcripción de hongos basales y su posible uso como diana para combatir la mucormicosis

Abstract

Fungal models have significantly advanced genetics over the past century, focusing primarily on Dikarya fungi while neglecting earlier branches of fungal evolution. Despite challenges in studying early-diverging fungi (EDF), such as difficulties in culture and genetic modification, these organisms hold increasing biotechnological and clinical interest, particularly Mucorales, which includes pathogens causing mucormycosis, a deadly infection recognized by the World Health Organization (WHO). Epigenetics, crucial for understanding processes like cell differentiation and cancer, is still largely unexplored in EDF, where 6-methyladenine (6mA) is the primary DNA epigenetic modification, unlike the 5-methylcytosine (5mC) found in higher eukaryotes. Research focused on two classic EDF models, Phycomyces blakesleeanus and Mucor lusitanicus, revealed distinct epigenomes. Phycomyces exhibited high 6mA levels associated with active gene expression, while Mucor displayed minimal methylation. Additionally, high 5mC levels were found in Phycomyces, contributing to genome defense. Exploring DNA modifications in EDF, we identified mechanisms for symmetric and asymmetric 6mA deposition, essential for gene regulation. Asymmetric methylation is controlled by MetB, possibly acquired through horizontal gene transfer, while symmetric methylation involves an MT-A70 complex conserved in unicellular eukaryotes. To deepen understanding of 6mA, we developed a CRISPR/Cas9 protocol for genetic manipulation in Rhizopus microsporus, a phytopathogenic fungus and mucormycosis agent, also valuable for studying fungal-bacterial interactions. Our comprehensive analysis of the R. microsporus epigenome revealed distinct chromatin compartments influenced by 6mA and histone modifications, impacting gene expression and chromatin structure. Downregulation of Mta1, a core component of the 6mA methylation complex, confirmed its role in gene regulation. These findings provide valuable insights into EDF epigenetics, offering potential targets for antifungal drug development. Future research should explore further aspects of EDF biology and utilize the molecular tools developed in this study.