title: Nuclear import of cutaneous beta genus HPV8 E7 oncoprotein is mediated by hydrophobic interactions between its zinc-binding domain and FG nucleoporins.
abstract: We have previously discovered and characterized the nuclear import pathways for the E7 oncoproteins of mucosal alpha genus HPVs, type 16 and 11. Here we investigated the nuclear import of cutaneous beta genus HPV8 E7 protein using confocal microscopy after transfections of HeLa cells with EGFP-8E7 and mutant plasmids and nuclear import assays in digitonin-permeabilized HeLa cells. We determined that HPV8 E7 contains a nuclear localization signal (NLS) within its zinc-binding domain that mediates its nuclear import. Furthermore, we discovered that a mostly hydrophobic patch 65LRLFV69 within the zinc-binding domain is essential for the nuclear import and localization of HPV8 E7 via hydrophobic interactions with the FG nucleoporins Nup62 and Nup153. Substitution of the hydrophobic residues within the 65LRLFV69 patch to alanines, and not R66A mutation, disrupt the interactions between the 8E7 zinc-binding domain and Nup62 and Nup153 and consequently inhibit nuclear import of HPV8 E7.
authors.affiliation: Biology Department, Boston College, Chestnut Hill, MA 02467, USA.
authors.forename: Zeynep
authors.initials: Z
authors.lastname: Onder
authors.affiliation: Biology Department, Boston College, Chestnut Hill, MA 02467, USA. Electronic address: moroianu@bc.edu.
authors.forename: Junona
authors.initials: J
authors.lastname: Moroianu
mesh_terms: D021581:Active Transport, Cell Nucleus; D052686:Betapapillomavirus / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism / Q000821:virology*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D019913:Nuclear Localization Signals; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000378:metabolism*; D050725:Papillomavirus E7 Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D030361:Papillomavirus Infections / Q000235:genetics / Q000378:metabolism* / Q000821:virology*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D016335:Zinc Fingers
chemical_list: D008562:Membrane Glycoproteins; C079377:NUP153 protein, human; D019913:Nuclear Localization Signals; D028861:Nuclear Pore Complex Proteins; D050725:Papillomavirus E7 Proteins; C049312:nuclear pore protein p62
keywords: Beta genus human papillomaviruses; EGFP; FG nucleoporins; GST; HPV; HPV8 E7 oncoprotein; NES; NLS; NPC; Nuclear localization signal; Nup153; Nup62; enhanced green fluorescent protein; glutathione-S-transferase; human papillomavirus; nuclear export signal; nuclear localization signal; nuclear pore complex