Molecular structures and replication fitness of HIV-1 intersubtype recombinants

描述(申请人提供)：开发艾滋病毒/艾滋病的抗病毒疗法和有效疫苗的主要障碍是病毒的高度变异性。重组是导致艾滋病毒-1种群迅速多样化的一个主要机制。我目前的研究重点是HIV-1亚型间重组的机制和限制因素。我们已经证明，二聚起始信号(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结构方面具有重要作用。为了进一步了解重组在HIV-1进化中的作用，我们调查了重组如何有助于复制适合性改变的重组子的产生。我们的长期目标是阐明病毒基因组中影响HIV-1重组体复制适合性的因素。这些病毒成分代表了阻止或加强重组的新的潜在靶点，这些重组可能会影响HIV-1在宿主中的持续复制。这项应用的目标是揭示1)在细胞培养和患者中产生的可存活的重组体的比例，2)这些重组体与野生型相比具有更好、相同和更差的复制适合性的比例，以及3)病毒基因组中决定复制适合性的元件。中心假设是，新产生的HIV-1亚型间重组体具有一系列复制适合度，并且HIV-1复制适合度有一个有限的窗口，允许重组子继续在宿主中复制。这一假设是基于这样的观察结果，即CRF02_AG比亲本的A和G亚型HIV-1具有更高的复制适合度，我们的初步数据表明，B和C亚型HIV-1之间的重组可以产生复制适合度改变的重组。这项研究的基本原理是，表征HIV-1亚型间重组体的复制适合性将使我们进一步了解产生具有生物学优势的新的HIV-1重组毒株的分子机制。其具体目的是：i)确定细胞培养来源的HIV-1亚型间重组体的复制适合性；ii)确定患者来源的HIV-1亚型间重组体的交叉连接的位置；以及iii)表征患者来源的HIV-1亚型间重组体的复制适合性。这项拟议的研究与公共卫生有关，因为确定复制适合性的已识别病毒成分可能代表着制定战略以防止艾滋病毒-1在人类宿主中持续复制的新目标。

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.