title: Human cytomegalovirus UL94 is a nucleocytoplasmic shuttling protein containing two NLSs and one NES.
abstract: The tegument protein UL94 is a human cytomegalovirus (HCMV) late protein and its function has yet to be determined. Using live cell fluorescence recovery after photobleaching (FRAP) and fluorescence loss in photobleaching (FLIP) imaging, we found that UL94 is able to shuttle between the nucleus and cytoplasm. Analysis of UL94 mutants fused to EGFP showed that two newly characterized nuclear localization sequences (NLSs) and amino acid 343 play key roles in UL94 nuclear localization. Mutation of these sequences can alter the intracellular distribution of UL94 and disrupt its nucleocytoplasmic shuttling. Amino acid 343 of UL94 was also found to be crucial for its interaction with another HCMV tegument protein pp28. Furthermore, one nuclear export sequence (NES) was identified within UL94. Mutation of the key amino acids in the NES can also alter the intracellular distribution of UL94 and disrupt its shuttling function. Like other proteins containing a leucine-rich export signal, nuclear export of the UL94 was affected by leptomycin B, indicating that it is exported via the Crm1-dependent pathway. Our data provide a basis for further understanding the character and function of HCMV UL94.
authors.affiliation: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
authors.forename: Yalan
authors.initials: Y
authors.lastname: Liu
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Zhang
authors.forename: Xing
authors.initials: X
authors.lastname: Zhao
authors.forename: Hongping
authors.initials: H
authors.lastname: Wei
authors.forename: Jiaoyu
authors.initials: J
authors.lastname: Deng
authors.forename: Zongqiang
authors.initials: Z
authors.lastname: Cui
authors.forename: Xian-En
authors.initials: XE
authors.lastname: Zhang
mesh_terms: D000818:Animals; D036022:Capsid Proteins / Q000235:genetics* / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism / Q000821:virology*; D002522:Chlorocebus aethiops; D003593:Cytoplasm / Q000378:metabolism / Q000821:virology*; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D008856:Microscopy, Fluorescence; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D021382:Protein Sorting Signals; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000032:analysis / Q000235:genetics; D014709:Vero Cells
chemical_list: D036022:Capsid Proteins; D050505:Mutant Proteins; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins; C415589:UL94 protein, Human cytomegalovirus; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins