The interaction between the measles virus nucleoprotein and the Interferon Regulator Factor 3 relies on a specific cellular environment

Background The genome of measles virus consists of a non-segmented single-stranded RNA molecule of negative polarity, which is encapsidated by the viral nucleoprotein (N) within a helical nucleocapsid. The N protein possesses an intrinsically disordered C-terminal domain (aa 401–525, NTAIL) that is exposed at the surface of the viral nucleopcapsid. Thanks to its flexible nature, NTAIL interacts with several viral and cellular partners. Among these latter, the Interferon Regulator Factor 3 (IRF-3) has been reported to interact with N, with the interaction having been mapped to the regulatory domain of IRF-3 and to NTAIL. This interaction was described to lead to the phosphorylation-dependent activation of IRF-3, and to the ensuing activation of the pro-immune cytokine RANTES gene.