Infection by HIV-1 CH042 constructs containing the AxxA or R191A mutation in Nef was associated with ~2-fold higher mRNA expression levels of the IFN-stimulated gene (ISG) MX1 encoding myxoma resistance protein 1 (Mx1), compared to WT HIV-1 infection (Fig. 1a). The gene discussed is MX1; the disease is HIV-1 infection.