Molecular structures and replication fitness of HIV-1 intersubtype recombinants

描述（由申请人提供）：开发HIV/AIDS抗病毒疗法和有效疫苗的主要障碍是病毒的高度变异性。艾滋病毒感染者的迅速多样化是一个主要机制。我目前的研究重点是HIV-1亚型间重组的机制和限制。我们已经表明，二聚化起始信号（DIS）序列是亚型间重组的主要决定因素，并且DIS在维持重组所需的二聚体RNA结构方面具有重要功能。为了进一步了解重组在HIV-1进化中的作用，我们研究了重组如何有助于产生具有改变的复制适应性的重组体。我们的长期目标是阐明病毒基因组中影响HIV-1重组体复制适应性的元件。这些病毒元件代表了阻断或增强重组的新的潜在靶点，这些重组可以影响HIV-1在宿主中的连续复制。本申请的目的是揭示1）在细胞培养物和存活的患者中产生的重组体的比例，2）与野生型相比，这些重组体将具有更好、相等和更差的复制适合度的比率，和3）病毒基因组中决定复制适合度的元件。核心假设是新产生的HIV-1亚型间重组体具有一系列复制适应性，并且HIV-1复制适应性有一个有限的窗口，允许重组体继续在宿主中复制。该假设基于以下观察结果：CRF 02_AG的复制适应度高于亲本亚型A和G HIV-1，我们的初步数据证明亚型B和C HIV-1之间的重组可以产生复制适应度改变的重组体。拟议研究的基本原理是，表征HIV-1亚型间重组体的复制适应性将使我们能够进一步了解产生具有生物学优势的新HIV-1重组株的分子机制。具体目的是：i）确定细胞培养物来源的HIV-1亚型间重组体的复制适合度，ii）鉴别患者来源的HIV-1亚型间重组体的交叉点位置，iii）表征患者来源的HIV-1亚型间重组体的复制适合度。拟议的研究与公共卫生有关，因为确定的决定复制适应性的病毒元件可能代表了制定预防HIV-1在人类宿主中持续复制的策略的新目标。

DESCRIPTION (provided by applicant): The main hindrance to develop antiviral therapies and effective vaccines for HIV/AIDS is the high variability of the virus. Recombination is a major mechanism that is responsible for this rapid diversification of HIV-1 population. My current research focuses on the mechanisms and restrictions in HIV-1 intersubtype recombination. We have shown that the dimerization initiation signal (DIS) sequence is a major determinant of intersubtype recombination and that the DIS has an important function in maintaining dimeric RNA structure important for recombination. To further understand the role of recombination in HIV-1 evolution, we investigate how recombination contributes to the generation of recombinants with altered replication fitness. Our long-term goal is to elucidate the elements in the viral genome that affect replication fitness of a HIV-1 recombinant. These viral elements represent new potential targets for blocking or enhancing recombination that can affect the continuous replication of HIV-1 in the host. The objectives of this application are to reveal 1) the proportion of recombinants generated in cell culture and patients that are viable, 2) the ratios at which these recombinants will have better, equal and worse replication fitness compared to wildtype and 3) the elements in viral genome that determine replication fitness. The central hypothesis is that newly generated HIV-1 intersubtype recombinants have an array of replication fitness and there is a finite window for HIV-1 replication fitness allowing the recombinants to continue to replicate in the host. This hypothesis is based on the observations that CRF02_AG has a higher replication fitness than the parental subtypes A and G HIV-1 and that our preliminary data demonstrated recombination between subtypes B and C HIV-1 can generate recombinant with altered replication fitness. The rationale of the proposed research is that characterizing the replication fitness of HIV-1 intersubtype recombinants will allow us to further understand the molecular mechanisms for generating new HIV-1 recombinant strains with biological advantages. The Specific Aims are to i) determine the replication fitness of cell culture-derived HIV-1 intersubtype recombinants, ii) identify the location of crossover junctions of patient-derived HIV-1 intersubtype recombinants, and iii) characterize the replication fitness of patient-derived HIV-1 intersubtype recombinants. The proposed research is relevant to public health because the identified viral elements that determine replication fitness may represent new targets for developing strategies to prevent the continuous replication of HIV-1 in the human hosts.