MX1 and viral infectious disease: Zhang et al.35 employed the Myxovirus resistance-1 (Mx1-Cre) system, where the Mx dynamin-like GTPase (Mx1) promotor is activated in an interferon-dependent manner following injection of polyinosinic:polycytidylic acid (poly I:C), a synthetic double-stranded RNA that mimics viral infection, resulting in the induced expression of the Cre recombinase transgene.