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Cellular requirements for the budding pathways of avian sarcoma virus and human immunodeficiency virus, type 1.

机译:禽肉瘤病毒和人类免疫缺陷病毒1型的出芽途径对细胞的要求

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摘要

The retroviral Gag polyprotein, the main structural component of virus particles, encodes all the elements necessary for assembly and release of VLPs from cells. Among these is the late assembly (L) domain, which functions as binding sites to recruit cellular proteins required for membrane scission and budding. Three classes of L domains, defined by conserved core motifs, exist within retroviruses and other enveloped virus families. The P(T/S)AP and YPxL motifs (both encoded by HIV-1 Gag) bind to components of the ESCRT pathway, Tsg101 and AIP1/Alix, respectively. The PPxY motif (encoded by ASV Gag) binds to Nedd4-like E3 ubiquitin ligases. Nedd4 ubiquitinates ASV Gag and links it to the ESCRT machinery for budding.;In the following study, we show that HIV-1 and ASV Gag utilize different components of the ESCRT pathway for budding. Covalently linking ESCRT proteins to the C-terminus of ASV Gag/Deltap2b and HIV-1 Gag/P7L rescues the budding defect caused by the L domain mutations. Though ESCRT-I proteins, Tsg101 and Vps37C, efficiently rescued ASV Gag/Deltap2b and HIV-1 Gag/P7L budding, siRNA-mediated depletion of these proteins in mammalian or avian cells did not affect ASV Gag release. The ESCRT-II protein, Eap20, partially rescues ASV Gag/Deltap2b, but did not rescue HIV-1 Gag/P7L. Consequently, siRNA knockdown of Eap20 inhibits ASV Gag release but not HIV-1 Gag. The ESCRT-III protein, Chmp6, rescued both ASV Gag/Deltap2b and HIV-1 Gag/P7L. Overexpression of a dominant-negative fragment of Chmp6 inhibited ASV and HIV VLP release indicating that both budding complexes required the ESCRT-III proteins for budding.We also observe that HIV and ASV VLPs bud from or pass through different cellular membranes during egress with ASV Gag associating the endosomal lipid analog, N-Rh-PE. ASV Gag derived particles, but not HIV-1 Gag particles, purified from N-Rh-PE-treated COS cells are labeled with the tracer. ASV Gag associates with N-Rh-PE in an L domain-dependent manner. The ASV Gag/Deltap2b-Eap20 chimera rescues budding through N-Rh-PE-positive membranes.;Finally, we show that the ubiquitin-like protein, ISG15, inhibits ASV and HIV-1 Gag budding. ISG15 prevents the interaction between the Gag budding complexes and Vps4E228Q. We correlate the inability to recruit Vps4 to the ISGylation of Chmp5.
机译:逆转录病毒Gag多蛋白是病毒颗粒的主要结构成分,编码从细胞中组装和释放VLP所需的所有元素。其中一个是晚期组装(L)结构域,其功能是作为结合位点以募集膜分裂和出芽所需的细胞蛋白。在逆转录病毒和其他包膜病毒家族中存在由保守的核心基序定义的三类L结构域。 P(T / S)AP和YPxL基序(均由HIV-1 Gag编码)分别与ESCRT途径的成分Tsg101和AIP1 / Alix结合。 PPxY主题(由ASV Gag编码)与Nedd4-like E3泛素连接酶结合。 Nedd4泛素化ASV Gag并将其链接到ESCRT机器进行出芽。在以下研究中,我们显示HIV-1和ASV Gag利用ESCRT途径的不同成分进行出芽。将ESCRT蛋白共价连接到ASV Gag / Deltap2b和HIV-1 Gag / P7L的C末端,可以挽救L结构域突变引起的萌芽缺陷。尽管ESCRT-1蛋白Tsg101和Vps37C有效挽救了ASV Gag / Deltap2b和HIV-1 Gag / P7L出芽,但是在哺乳动物或禽类细胞中siRNA介导的这些蛋白的消耗并不影响ASV Gag的释放。 ESCRT-II蛋白Eap20可部分拯救ASV Gag / Deltap2b,但不能拯救HIV-1 Gag / P7L。因此,Eap20的siRNA抑制可抑制ASV Gag释放,但不能抑制HIV-1 Gag。 ESCRT-III蛋白Chmp6拯救了ASV Gag / Deltap2b和HIV-1 Gag / P7L。 Chmp6显性负片段的过表达抑制了ASV和HIV VLP的释放,这表明这两个出芽复合物都需要ESCRT-III蛋白来出芽。结合内体脂质类似物N-Rh-PE。用示踪剂标记从N-Rh-PE处理过的COS细胞中纯化得到的ASV Gag衍生颗粒,而不是HIV-1 Gag颗粒。 ASV Gag以L域依赖的方式与N-Rh-PE关联。 ASV Gag / Deltap2b-Eap20嵌合体通过N-Rh-PE阳性膜营救出芽。最后,我们证明了泛素样蛋白ISG15抑制了ASV和HIV-1 Gag出芽。 ISG15阻止Gag萌芽复合体和Vps4E228Q之间的相互作用。我们将无法招募Vps4与Chmp5的ISGylation相关联。

著录项

  • 作者

    Pincetic, Andrew.;

  • 作者单位

    Northwestern University.;

  • 授予单位 Northwestern University.;
  • 学科 Biology Virology.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 118 p.
  • 总页数 118
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

  • 入库时间 2022-08-17 11:38:26

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