Progressive multifocal leukoencephalopathy-associated mutations in the JC polyomavirus capsid disrupt lactoseries tetrasaccharide c binding.
Progressive multifocal leukoencephalopathy-associated mutations in the JC polyomavirus capsid disrupt lactoseries tetrasaccharide c binding.
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DOI：
10.1128/mbio.00247-13
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发表时间：
2013-06-11
期刊：
影响因子：
6.4
通讯作者：
Atwood WJ
中科院分区：
文献类型：
--
作者：
Maginnis MS;Ströh LJ;Gee GV;O'Hara BA;Derdowski A;Stehle T;Atwood WJ
人JC多瘤病毒（JCPyV）是致死性脱髓鞘疾病进行性多灶性白质脑病（PML）的病原体。JCPyV的Mad-1原型菌株分别使用聚糖乳糖系列四糖c（LSTc）和5-羟色胺受体5-HT 2A附着和进入宿主细胞。病毒衣壳蛋白VP 1中的特定残基负责与LSTc的α 2，6-连接唾液酸直接相互作用。来自PML患者的病毒分离株通常在VP 1的唾液酸结合口袋中含有突变，推测这些突变是由阳性选择引起的。我们在JCPyV的Mad-1菌株中重建了这些突变，发现它们不能生长。然后将突变引入重组VP 1中并重构为五聚体以进行结合研究和结构分析。携带PML相关突变的VP 1五聚体不能与允许细胞结合。高分辨率结构测定显示，这些五聚体折叠良好，但由于唾液酸结合位点的空间冲突，不再与LSTc结合。将突变重建到JCPyV假病毒中使我们能够直接定量几种细胞系中突变体的感染性。具有PML相关突变的JCPyV假病毒不具有感染性，也不能与唾液酸结合，如通过人红细胞的血凝所测量的。这些结果表明，来自具有VP 1单点突变的PML患者的病毒破坏了与唾液酸基序的结合，并使这些病毒无感染性。人JC多瘤病毒（JCPyV）感染在健康个体中很常见且无症状，但在免疫抑制期间，JCPyV可从肾脏传播到中枢神经系统（CNS），并引起致命的脱髓鞘疾病，即进行性多灶性白质脑病（PML）。HIV感染者、AIDS患者或接受自身免疫性疾病免疫调节治疗的患者有发生PML的严重风险。最近的报道表明，从PML患者分离的病毒通常在主要衣壳蛋白内具有明显的变化。我们的结构-功能方法强调，这些突变导致感染所必需的碳水化合物受体基序LSTc的参与被取消。PML相关突变的病毒在神经胶质细胞中不具有感染性，这表明它们可能在PML发病机制中发挥替代作用。
The human JC polyomavirus (JCPyV) is the causative agent of the fatal, demyelinating disease progressive multifocal leukoencephalopathy (PML). The Mad-1 prototype strain of JCPyV uses the glycan lactoseries tetrasaccharide c (LSTc) and serotonin receptor 5-HT2A to attach to and enter into host cells, respectively. Specific residues in the viral capsid protein VP1 are responsible for direct interactions with the α2,6-linked sialic acid of LSTc. Viral isolates from individuals with PML often contain mutations in the sialic acid-binding pocket of VP1 that are hypothesized to arise from positive selection. We reconstituted these mutations in the Mad-1 strain of JCPyV and found that they were not capable of growth. The mutations were then introduced into recombinant VP1 and reconstituted as pentamers in order to conduct binding studies and structural analyses. VP1 pentamers carrying PML-associated mutations were not capable of binding to permissive cells. High-resolution structure determination revealed that these pentamers are well folded but no longer bind to LSTc due to steric clashes in the sialic acid-binding site. Reconstitution of the mutations into JCPyV pseudoviruses allowed us to directly quantify the infectivity of the mutants in several cell lines. The JCPyV pseudoviruses with PML-associated mutations were not infectious, nor were they able to engage sialic acid as measured by hemagglutination of human red blood cells. These results demonstrate that viruses from PML patients with single point mutations in VP1 disrupt binding to sialic acid motifs and render these viruses noninfectious. Infection with human JC polyomavirus (JCPyV) is common and asymptomatic in healthy individuals, but during immunosuppression, JCPyV can spread from the kidney to the central nervous system (CNS) and cause a fatal, demyelinating disease, progressive multifocal leukoencephalopathy (PML). Individuals infected with HIV, those who have AIDS, or those receiving immunomodulatory therapies for autoimmune diseases are at serious risk for PML. Recent reports have demonstrated that viral isolates from PML patients often have distinct changes within the major capsid protein. Our structural-functional approach highlights that these mutations result in abolished engagement of the carbohydrate receptor motif LSTc that is necessary for infection. Viruses with PML-associated mutations are not infectious in glial cells, suggesting that they may play an alternative role in PML pathogenesis.