FIG. 4.

IRF-3 contains a nuclear export sequence that binds the exportin CRM1. HEC-1B cells were transfected with GFP–wt IRF-3 (wt) (a and b) or the NES mutation GFP–IRF-3 (IL 139/140 MM) (c and d) and were left untreated (a and c) or were infected with NDV as indicated (b and d). The effect of leptomycin (LMP) on localization of GFP–wt IRF-3 is shown (e). (f) CRM1 exportin binding to IRF-3 in vitro. CRM1 was synthesized in vitro in the presence of [³⁵S]methionine (relative input shown on right) and was incubated with either GST, GST–IRF-3, or GST-NES from PKI. The binding was performed in the presence or absence of bacterially expressed Ran (Q69L) protein and a peptide corresponding to the NES of the Rev protein.