首页> 外文学位 >VPU mediated enhancement of human immunodeficiency virus pathogenesis: The role of conserved and unique domains in protein function.
【24h】

VPU mediated enhancement of human immunodeficiency virus pathogenesis: The role of conserved and unique domains in protein function.

机译:VPU介导的人类免疫缺陷病毒发病机理的增强:保守和独特域在蛋白质功能中的作用。

获取原文
获取原文并翻译 | 示例

摘要

The work in this dissertation examined the biological characteristics of different HIV-1 Vpu subtypes, with an emphasis on subtypes B and C, and the potential impact of these proteins on SHIV pathogenesis. Different Vpu subtypes exhibited distinct biological properties that potentially could affect HIV-1 pathogenesis and/or transmission efficiency, including intracellular localization, efficiency in down-modulating CD4 surface expression, and the ability to enhance virion release in HeLa cells. We show for the first time that the subtype B and C Vpu proteins partitioned into detergent resistant membranes (DRMs), a property characteristic of lipid raft association. We also identified two mutants, IVV19-21AAA and W22A, that prevented this association. Additionally, we found a correlation between the ability of Vpu to stably associate with DRMs and the ability to enhance virion release in HeLa cells. Analysis of different Vpu proteins from clinical isolates identified a membrane proximal tyrosine motif (YXXphi) that is highly conserved among all Vpu subtypes and an overlapping dileucine motif ([D/E]xxxL[L/I]) that is conserved among subtype C Vpu proteins. Substitution of the tyrosine residue in the YXXphi motif with an alanine (Y35A) significantly inhibited SHIV replication while substitution of the primary leucine residue with a glycine (L39G) in the overlapping [D/E]xxxL[L/I] motif significantly increased the amount of virus released from C8166 cells and the mean number of viral particles per cell compared to cells inoculated with the parental SHIVSCVpu. Recently, the enhanced virion release function of Vpu has been attributed to the antagonism of bone marrow stromal antigen 2 (BST-2) protein. This has been shown to involve the transmembrane domains (TMD) of both proteins. Our results indicate that the length of the BST-2 TMD is more important than the primary sequence both for the function and sensitivity of the protein. Additionally, we showed that the BST-2 protein expressed in pig-tailed macaques is not antagonized by HIV-1 Vpu, but rather by SIV Nef, thus indicating a species-specific basis for this antagonism. Based on these results we continued our analyses by examining the biological characteristics of SHIV expressing either a subtype B (SHIV KU-1bMC33) or C (SHIVSCVpu) Vpu protein. SHIVSCVpu caused a more gradual rate of CD4+ T cell loss and lower peak viral loads in infected pig-tailed macaques compared to macaques inoculated with SHIVKU-1bMC33. The identification of the TMD and the putative sorting signals proximal to the membrane as key determinants in Vpu-mediated enhanced virion release prompted the hypothesis that these two regions may dictate these differences in pathogenesis. Therefore, we constructed chimeric Vpu proteins in which the N-terminus/TMD regions of the subtype B and C Vpu proteins were exchanged (VpuBC and VpuCB). Inoculation of pig-tailed macaques with SHIVVpuCB resulted in a more gradual loss of circulating CD4+ T cells compared to SHIVVpuBC-inoculated macaques, but more rapid than resulted in macaques inoculated with parental SHIVSCVpu. Since both of these proteins down-modulated CD4 surface expression similar to the unmodified VpuSCEGFP1 protein, our results indicate that the differences observed in CD4 surface down-modulation in vitro are most likely not physiologically relevant. Finally, as pig-tailed macaques express a BST-2 protein that is not affected by the HIV-1 Vpu protein, our results suggest that the enhanced virion release function of different Vpu subtypes as observed during an intravenous inoculation may be dependent upon a different factor(s). The work presented here demonstrates a clear potential for differential signaling and functional efficiency among all HIV-1 Vpu subtypes with the ability to modify pathogenesis. Additionally, our analyses identified the TMD and membrane proximal regions as crucial components to Vpu enhancement of pathogenesis providing novel information essential for anti-retroviral therapeutic development.
机译:本文研究了不同HIV-1 Vpu亚型的生物学特性,重点是B和C亚型,以及这些蛋白对HIV感染的潜在影响。不同的Vpu亚型表现出不同的生物学特性,这些特性可能会影响HIV-1的发病机理和/或传播效率,包括细胞内定位,下调CD4表面表达的效率以及增强HeLa细胞中病毒体释放的能力。我们第一次表明,亚型B和C Vpu蛋白被划分成抗洗涤剂膜(DRMs),脂筏协会的特性。我们还确定了阻止这种关联的两个突变体,IVV19-21AAA和W22A。此外,我们发现Vpu与DRM稳定缔合的能力与增强HeLa细胞中病毒体释放的能力之间存在相关性。对来自临床分离株的不同Vpu蛋白进行分析后,发现在所有Vpu亚型中高度保守的膜近端酪氨酸基序(YXXphi)和在C Vpu亚型中保守的重叠双亮氨酸基序([D / E] xxxL [L / I])蛋白质。 YXXphi基序中的酪氨酸残基被丙氨酸(Y35A)取代显着抑制了SHIV复制,而重叠的[D / E] xxxL [L / I]基序中的甘氨酸(L39G)取代了初级亮氨酸残基则显着增加了SHIV复制。与接种亲本SHIVSCVpu的细胞相比,C8166细胞释放的病毒数量以及每个细胞的平均病毒颗粒数。最近,Vpu的病毒体释放功能增强已归因于骨髓基质抗原2(BST-2)蛋白的拮抗作用。已经显示这涉及两种蛋白的跨膜结构域(TMD)。我们的结果表明,对于蛋白质的功能和敏感性,BST-2 TMD的长度比一级序列更重要。此外,我们表明在猪尾猕猴中表达的BST-2蛋白不是被HIV-1 Vpu所拮抗,而是被SIV Nef所拮抗,因此表明了这种拮抗作用的物种特异性基础。基于这些结果,我们通过检查表达B型(SHIV KU-1bMC33)或C型(SHIVSCVpu)Vpu蛋白的SHIV的生物学特性,继续进行分析。与接种SHIVKU-1bMC33的猕猴相比,SHIVSCVpu导致受感染的猪尾猕猴的CD4 + T细胞丢失率更高,峰值病毒载量更低。 TMD和膜近端的假定分选信号的鉴定是Vpu介导的增强病毒体释放的关键决定因素,这提示了以下假设:这两个区域可能决定了发病机理的差异。因此,我们构建了嵌合的Vpu蛋白,其中B型和C型Vpu蛋白的N末端/ TMD区被交换(VpuBC和VpuCB)。与用SHIVVpuBC接种的猕猴相比,用SHIVVpuCB接种猪尾猕猴会导致循环CD4 + T细胞的逐渐消失,但比接种亲代SHIVSCVpu的猕猴更快。由于这两种蛋白都下调了CD4表面表达,类似于未修饰的VpuSCEGFP1蛋白,因此我们的结果表明,体外CD4表面下调所观察到的差异很可能与生理无关。最后,由于猪尾猕猴表达不受HIV-1 Vpu蛋白影响的BST-2蛋白,因此我们的结果表明,静脉内接种期间观察到的不同Vpu亚型增强的病毒体释放功能可能取决于不同的因素。此处介绍的工作证明,在所有具有HIV-1 Vpu亚型且具有改变发病机理能力的差异性信号传导和功能效率中,均具有明显的潜力。此外,我们的分析确定了TMD和膜近端区域是Vpu增强发病机理的关键组成部分,为抗逆转录病毒疗法的发展提供了重要的新信息。

著录项

  • 作者

    Ruiz, Autumn Joy.;

  • 作者单位

    University of Kansas.;

  • 授予单位 University of Kansas.;
  • 学科 Biology Molecular.;Biology Virology.;Biology Cell.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 380 p.
  • 总页数 380
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号