Characterization of the nuclear import and export mechanisms of bovine herpesvirus-1 infected cell protein 27.
In previous study, we have identified a nuclear localization signal (NLS) and a nucleolar localization signal (NoLS) in bovine herpesvirus-1 (BHV-1) infected cell protein 27 (BICP27), which targets predominantly to the nucleolus. Furthermore, the C-terminal 300 amino acid residues targets exclusively to the cytoplasm, suggesting that BICP27 might contain a nuclear export signal (NES). Amino acid sequence analysis revealed that there is a cluster of leucine-rich residues resembling a NES. Heterokaryon assays demonstrated that BICP27 is capable of shuttling between the nucleus and the cytoplasm of the BHV-1 infected, BICP27 and BICP27-EYFP transfected cells. Deletion mutant analysis revealed that this property is attributed to the leucine-rich NES 299LEELCAARRLSL310. Moreover, the functional NES could mediate transport of a monomer EYFP and a dimer EYFP to the cytoplasm. The nucleocytoplasmic shuttling of BICP27 and the nuclear export of NES-EYFP and NES-dEYFP could be blocked by leptomycin LMB, an inhibitor of the chromosomal region maintenance 1 (CRM1), which is the receptor for exportin-1-dependent nuclear export. In addition, the nuclear import of BICP27 was inhibited by a dominant negative Ran-GTP, namely Ran-GTP Q69L, indicating that BICP27 localized to the nucleus by means of a classic Ran dependent nuclear import mechanism. In conclusion, these results demonstrate that BICP27 shuttles between the nucleus and the cytoplasm by the functional NES and NLS through a CRM1-dependent nuclear export pathway and a Ran dependent nuclear import pathway.
Ding
Qiong
Q
State Key Laboratory of Virology, Molecular Virology and Viral Immunology Research Group, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei 430071, PR China.
Guo
Hong
H
Lin
Fusen
F
Pan
Weiwei
W
Ye
Bin
B
Zheng
Alan C
AC
D021581:Active Transport, Cell Nucleus; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D004252:DNA Mutational Analysis; D019281:Dimerization; D007242:Herpesvirus 1, Bovine / Q000502:physiology*; D017874:Immediate-Early Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D041681:NIH 3T3 Cells; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D021382:Protein Sorting Signals; D021381:Protein Transport; D017384:Sequence Deletion
C099232:BICP27 protein, Bovine herpesvirus 1; D017874:Immediate-Early Proteins; D010750:Phosphoproteins; D021382:Protein Sorting Signals