Nuclear import of cutaneous beta genus HPV8 E7 oncoprotein is mediated by hydrophobic interactions between its zinc-binding domain and FG nucleoporins

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• 作者：Zeynep Onder ; Junona Moroianu
• 关键词：HPV ; human papillomavirus ; NLS ; nuclear localization signal ; NES ; nuclear export signal ; NPC ; nuclear pore complex ; EGFP ; enhanced green fluorescent protein ; GST ; glutathione-S-transferase
• 刊名：Virology
• 出版年：20 January, 2014
• 年：2014
• 卷：449
• 期：Complete
• 页码：150-162
• 全文大小：2937 K

文摘

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.