title: The nuclear localization of low risk HPV11 E7 protein mediated by its zinc binding domain is independent of nuclear import receptors.
abstract: We investigated the nuclear import of low risk HPV11 E7 protein using 1) transfection assays in HeLa cells with EGFP fusion plasmids containing 11E7 and its domains and 2) nuclear import assays in digitonin-permeabilized HeLa cells with GST fusion proteins containing 11E7 and its domains. The EGFP-11E7 and EGFP-11cE7(39-98) localized mostly to the nucleus. The GST-11E7 and GST-11cE7(39-98) were imported into the nuclei in the presence of either Ran-GDP or RanG19V-GTP mutant and in the absence of nuclear import receptors. This suggests that 11E7 enters the nucleus via a Ran-dependent pathway, independent of nuclear import receptors, mediated by a nuclear localization signal located in its C-terminal domain (cNLS). This cNLS contains the zinc binding domain consisting of two copies of Cys-X-X-Cys motif. Mutagenesis of Cys residues in these motifs changed the localization of the EGFP-11cE7/-11E7 mutants to cytoplasmic, suggesting that the zinc binding domain is essential for nuclear localization of 11E7.
authors.affiliation: Biology Department, Boston College, Chestnut Hill, MA 02467, USA.
authors.forename: Zachary
authors.initials: Z
authors.lastname: Piccioli
authors.forename: Courtney H
authors.initials: CH
authors.lastname: McKee
authors.forename: Anna
authors.initials: A
authors.lastname: Leszczynski
authors.forename: Zeynep
authors.initials: Z
authors.lastname: Onder
authors.forename: Erin C
authors.initials: EC
authors.lastname: Hannah
authors.forename: Shahan
authors.initials: S
authors.lastname: Mamoor
authors.forename: Lauren
authors.initials: L
authors.lastname: Crosby
authors.forename: Junona
authors.initials: J
authors.lastname: Moroianu
mesh_terms: D021581:Active Transport, Cell Nucleus; D020816:Amino Acid Motifs; D019677:Artificial Gene Fusion; D001665:Binding Sites; D002467:Cell Nucleus / Q000737:chemistry; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D052140:Human papillomavirus 11 / Q000502:physiology*; D006801:Humans; D016297:Mutagenesis, Site-Directed; D009856:Oncogene Proteins, Viral / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D014162:Transfection; D014779:Virus Replication; D020931:ran GTP-Binding Protein / Q000378:metabolism
chemical_list: C493190:E7 protein, human papillomavirus 11; D009856:Oncogene Proteins, Viral; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D020931:ran GTP-Binding Protein
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