A functional nuclear localization sequence in the VP1 capsid protein of coxsackievirus B3

The capsid proteins of some RNA viruses can translocate to the nucleus and interfere with cellular phenotypes. In this study we found that the VP1 capsid protein of coxsackievirus B3 (CVB3) was dominantly localized in the nucleus of the cells transfected with VP1-expressing plasmid. The VP1 nuclear localization also occurred in the cells infected with CVB3. Truncation analysis indicated that the VP1 nuclear localization sequence located near the C-terminal. The substitution of His220 with threonine completely abolished its translocation. The VP1 proteins of other CVB types might have the nuclear localization potential because this region was highly conserved. Moreover, the VP1 nuclear localization induced cell cycle deregulation, including a prolonged S phase and shortened G2-M phase. Besides these findings, we also found a domain between Ala72 and Phe106 that caused the VP1 truncates dotted distributed in the cytoplasm. Our results suggest a new pathogenic mechanism of CVB.