Role of V1V2 in HIV transmission and pathogenesis

描述（由申请人提供）：尽管晶体学研究已经提供了HIV-1表面糖蛋白（gp120）保守核心结构的详细描述，但对前两个高变区（VIV2）的结构和功能知之甚少，它们从核心表面突出，并且在疾病过程中经常经历广泛的插入和缺失。从VIV2结构域去除糖基化位点或删除氨基酸残基可以影响许多对病毒进入至关重要的分子相互作用。然而，这些研究可能不能完全描述V1V2的自然功能，并且很少有研究全面检查在病毒传播或疾病进展期间V1V2区域内自然变异性的后果。在这里，我们将定义自然发生的V1V2区域的结构-功能关系，因为它们与来自赞比亚大量异性恋夫妇群体的Env分子中的异性传播和病毒进化有关。我们的初步研究表明，在8对异性传播对的受体伴侣中发现了一个具有紧凑长度和限制n -链糖基化的同质病毒群体；然而，每个供体伴侣的病毒准种包含多达9种不同的VIV2变体，大小可达3倍，糖基化位点数量可达9倍。这些数据表明异性传播的分子决定因素与V1V2的结构有关，V1V2嵌合的Envs将由5个构建！传输对和用来定义这种关系。为了更好地理解急性感染期后VIV2中出现的广泛变异，将在同一队列中从10个新发现的血清转化者中收集至少3年的纵向样本，跟踪VIV2序列进化过程。我们将构建v1v2 -嵌合Env分子来研究感染期间VIV2区域内时间变化的生物学后果。通过这些研究，我们将验证以下假设：具有紧凑V1V2区域的病毒建立了感染，并且在感染过程中出现了长度和糖基化的逐渐增加，这有助于免疫逃避和复制适应性，但干扰了病毒传播。

DESCRIPTION (provided by applicant): Although crystallographic studies have provided a detailed description of the conserved core structure of the HIV-1 surface glycoprotein (gp120), much less is known about the structure and function of the first two hyper-variable regions (VIV2), which protrude from the core surface and often undergo extensive insertions and deletions over the course of disease. Elimination of glycosylation sites or deletion of amino acid residues from the VIV2 domain can influence a number of molecular interactions that are critical to virus entry. However, such studies may not fully describe the natural functions of V1V2, and few studies have comprehensively examined the consequences of natural variability within the V1V2 region during virus transmission or disease progression. Here we will define the structure-function relationships of naturally occurring V1V2 regions as they pertain to heterosexual transmission and virus evolution in Env molecules derived from a large heterosexual couple cohort in Zambia. Our preliminary studies demonstrated that a homogeneous virus population with compact length and restricted N-linked glycosylation in VIV2 were found in the recipient partners of eight heterosexual transmission pairs; however, the viral quasispecies of each donor partner contained up to nine different VIV2 variants, ranging as much as 3-fold in size and 9-fold in the number of glycosylation sites. These data suggest that the molecular determinants of heterosexual transmission are related to the structure of V1V2, and V1V2-chimeric Envs will be constructed from five !transmission pairs and utilized to define this relationship. To better understand the extensive variation that emerges in VIV2 following the acute infection period, the course of sequence evolution in VIV2 will be followed in longitudinal samples collected over a minimum of three years from ten newly identified seroconvertors in the same cohort. We will construct V1V2-chimeric Env molecules to investigate the ,biological consequences of temporal changes within the VIV2 region during infection. Through these studies, we will test the hypotheses that viruses with compact V1V2 regions establish infection and that progressive increases in length and glycosylation arise over the course of infection that contribute to immune evasion and replication fitness, but interfere with virus transmission.