Université de Lyon and Université Lyon 1, Lyon, France.
J Virol. 2012 Feb;86(3):1449-57. doi: 10.1128/JVI.06194-11. Epub 2011 Nov 30.
Herpes simplex virus type 1 (HSV-1) infection induces profound nucleolar modifications at the functional and organizational levels, including nucleolar invasion by several viral proteins. One of these proteins is US11, which exhibits several different functions and displays both cytoplasmic localization and clear nucleolar localization very similar to that of the major multifunctional nucleolar protein nucleolin. To determine whether US11 interacts with nucleolin, we purified US11 protein partners by coimmunoprecipitations using a tagged protein, Flag-US11. From extracts of cells expressing Flag-US11 protein, we copurified a protein of about 100 kDa that was further identified as nucleolin. In vitro studies have demonstrated that nucleolin interacts with US11 and that the C-terminal domain of US11, which is required for US11 nucleolar accumulation, is sufficient for interaction with nucleolin. This association was confirmed in HSV-1-infected cells. We found an increase in the nucleolar accumulation of US11 in nucleolin-depleted cells, thereby revealing that nucleolin could play a role in US11 nucleocytoplasmic trafficking through one-way directional transport out of the nucleolus. Since nucleolin is required for HSV-1 nuclear egress, the interaction of US11 with nucleolin may participate in the outcome of infection.
单纯疱疹病毒 1 型 (HSV-1) 感染会在功能和组织水平上引起深刻的核仁改变，包括几种病毒蛋白入侵核仁。其中一种蛋白质是 US11，它具有多种不同的功能，表现出细胞质定位和清晰的核仁定位，与主要多功能核仁蛋白核仁素非常相似。为了确定 US11 是否与核仁素相互作用，我们使用标记蛋白 Flag-US11 通过共免疫沉淀来纯化 US11 蛋白伴侣。从表达 Flag-US11 蛋白的细胞提取物中，我们共纯化了一种约 100 kDa 的蛋白质，进一步鉴定为核仁素。体外研究表明核仁素与 US11 相互作用，并且 US11 核仁积累所必需的 C 末端结构域足以与核仁素相互作用。在 HSV-1 感染的细胞中证实了这种关联。我们发现，在核仁素耗尽的细胞中，US11 的核仁积累增加，从而揭示核仁素可能通过单向从核仁向外的核质转运来在 US11 的核质运输中发挥作用。由于核仁素是 HSV-1 核输出所必需的，因此 US11 与核仁素的相互作用可能参与感染的结果。
