Characterization of a CRM1-Dependent Nuclear Export Signal in the C Terminus of Herpes Simplex Virus Type 1 Tegument Protein UL47

The herpes simplex virus type 1 tegument protein known as VP13/14, or hUL47, localizes to the nucleus and binds RNA. Using fluorescence loss in photobleaching analysis, we show that hUL47 undergoes nucleocytoplasmic shuttling during infection. We identify the hUL47 nuclear export signal (NES) as a C-terminal 10-residue hydrophobic peptide and measure its efficiency relative to that of the classical human immunodeficiency virus type 1 Rev NES. Finally, we show that the hUL47 NES is sensitive to the inhibitor of CRM1-mediated nuclear export leptomycin B. Hence, hUL47 joins a growing list of virus-encoded RNA-binding proteins that use CRM1 to exit the nucleus.