EARLY STAGES OF INFECTION BY NONENVELOPED VIRUSES

描述：人类脊髓灰质炎病毒受体(PVR)的特征导致 详细描述了进入过程的初始阶段，即 病毒与受体的相互作用。然而，动力学和遗传学证据也 表示存在涉及膜的其他阶段 相互作用，仍然知之甚少。在这份修订后的申请中，Dr。 阿肯色大学的Chow和她的合作者M.Tosteson博士 哈佛大学将评估两种可行的RNA传递模型 细胞质。这两个模型都需要本地(160)粒子相互作用 用PVR产生一个“进入活跃”的粒子，这改变了 颗粒与宿主细胞膜相互作用。最简单的模型提出 在PVR相互作用后，只有RNA基因组被直接运输 通过病毒特异的离子渗透通道穿过质膜。 第二种模式涉及“主动递送”病毒的传播。 颗粒穿过细胞膜进入细胞质，随后释放 粒子中的核糖核酸。为了剖析这些早期事件，建议的 研究将建立在周博士和Tosteson博士最近观察到的 强效病毒在模型膜中产生离子渗透通道。在 第一个目的是，申请人建议表征电导、动力学 通道的特性和管腔大小。他们还将分别 确定对接病毒颗粒对通道形成的影响 使用PVR与使用带有抗体包被颗粒的Fc受体相比。 他们还将监测粒子通道形成过程中产生的效应 结合Win药物或多肽特异性抗体的特性。这个 第二个目标是确定与膜有关的衣壳蛋白结构域。 并定义它们在病毒入侵中的角色。现有的和新的 VP4或VP1 N端进入缺陷的构建突变体 将使用模型膜检查通道中的任何变化 特性；如果发现，这些特性将与生物表型相关。 据悉，这些研究将为生物化学和生物化学提供 通道结构的生物物理组成，并允许申请人 建立非包膜病毒感染早期的一般模型 病毒。

DESCRIPTION: Characterization of human poliovirus receptor (PVR) has led to a detailed description of the initial stage of the entry process, the virus-receptor interaction. However, kinetic and genetic evidence also indicate the existence of additional stages which involve membrane interactions and remain poorly understood. In this revised application, Dr. Chow at the University of Arkansas and her collaborator, Dr. M. Tosteson at Harvard, will evaluate two plausible models of RNA delivery into the cytoplasm. Both models require that the native (160S) particles interact with PVR to generate an "entry-active" particle and that this altered particle interacts with host cell membranes. The simplest model proposes that, after PVR interaction, only the RNA genome is transported directly across the plasma membrane through virus-specific ion-permeable channels. The second model involves the passage of the "delivery active" virus particle across the membrane into the cytoplasm and subsequent release of the RNA from the particle. To dissect these early events, the proposed studies will build on Drs. Chow and Tosteson's recent observation that entry competent viruses produce ion-permeable channels in model membranes. In the first Aim, the applicants propose to characterize conductance, kinetic characteristics and lumen size of the channels. They will also separately determine the effects on channel formation of docking the virus particles using the PVR versus using an Fc receptor with antibody coated particles. They also will monitor effects induced in the particle's channel forming properties from binding Win drugs or peptide specific antibodies. The second Aim will characterize the capsid protein domains involved in membrane interaction and define their roles in virus entry. Existing and newly constructed mutants in VP4 or in the N-terminus of VP1 defective in entry will be examined using model membranes for any changes in channel properties; if found, these will be correlated with biological phenotypes. It is aticipated that the studies will provide the biochemical and biophysical make-up of the channel structure and allow the applicants to build a general model of the early stages of infection by nonenveloped viruses.