Identification and characterisation of G-quadruplexes from viral genomes

G-quadruplexes (G4s) are non-canonical structures identified in all domains of life. In humans, they have been shown to influence a number of biological processes. Our lab has recently identified G4s in viruses containing RNA or DNA as the genetic material using bioinformatics tools and characterized them using biophysical methods such as circular dichroism, and small angle X-ray scattering. For example, we recently established that the Zika virus that contains RNA as its genetic material has a conserved G4 present in its 3′ terminal region. A mutation from G to A nucleotide severely disrupts G4 formation, and the ability of Zika virus G4 to interact with known G4 interacting partners such as DHX36 and G4-binding antibodies. We also demonstrated that Zika virus G4 can be recognized and unwinded by human helicase DDX17. Subsequently, we discovered that the Monkeypox virus which consists of a DNA genome contains two conserved G4s, which are not present in any other pox viruses. After establishing G4 formation using short wild-type and mutant constructs of Monkeypox DNA using biophysical methods, we also demonstrated that a quadruplex binding small-molecule, TMPyP4, that was previously reported to reduce viral replication interacts with Monkeypox G4s with nanomolar affinity. Overall, our work provides novel targets against which antivirals can be developed.