Viruses were once thought to be the sole source of long double-stranded RNA (dsRNA) in animal cells, but the Bass laboratory identified numerous long dsRNAs that are genomically encoded and expressed in animals, including humans. dsRNA-binding proteins enable cells to distinguish the “good” cellular dsRNA from the “bad” viral dsRNA, but how they do this is not completely understood. Our current studies are focused on how a conserved helicase domain distinguishes “self” versus “non-self” dsRNA, and how this function has diverged in vertebrates and invertebrates. We used ancestral sequence reconstruction to infer amino acid sequences of the helicase domain of ancestral Dicers, enabling comparisons of its enzymatic activity with that of modern-day Dicer enzymes.
Brenda Bass