The nuclear localization of low risk HPV11 E7 protein mediated by its zinc binding domain is independent of nuclear import receptors.
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.
Piccioli
Zachary
Z
Biology Department, Boston College, Chestnut Hill, MA 02467, USA.
McKee
Courtney H
CH
Leszczynski
Anna
A
Onder
Zeynep
Z
Hannah
Erin C
EC
Mamoor
Shahan
S
Crosby
Lauren
L
Moroianu
Junona
J
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
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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