Role of Chromatin Associated Host Factors in Regulation of Retroviral Replication

点击翻译按钮获取中文摘要

Project Summary A number of host cell factors are known to bind the retroviral integrase (IN) protein and facilitate its functions. In preliminary studies we have identified a novel set of host factors that bind the IN protein. These host factors include histone chaperones, chromatin remodelers and histone variants. In the proposed research, we will determine the effect of these identified candidate host factors on retroviral replication, testing multiple genera of retroviruses including alpha-, beta-, gammaretroviruses as well as lentiviruses. We will further determine how the host factor is affecting replication by analyzing viral intermediates to uncover the specific step at which the host factor acts. We will perform integration site mapping in the presence and absence of candidate host factors to determine the effects on integration targeting in the human genome. The proviral genome is rapidly loaded with histones upon entry into the host cell nucleus. We hypothesize that these host factors may also be facilitating histone loading due to their histone chaperone function. Therefore, we also propose to evaluate histone loading onto the proviral genome in wild type vs. host factor knockdown cells. Further, the identified host factors include chromatin remodelers that play a role in spacing nucleosomes into patterned arrays and thus we will analyze nucleosome occupancy profile on the viral genome as a function of host factor abundance. Lastly, the IN protein appears to bind H2A histone variants, and thus we will determine whether these histone variants are recruited and deposited on the proviral genome. We will further determine if histone variants affect viral replication through knockout studies. We expect that these studies will reveal new aspects of retrovirus replication and therefore define entirely new targets for intervention. !