Remodeling of the nuclear membrane during herpesvirus assembly

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Much of what we understand about the fundamental processes that enable cells to proliferate and to perform specific biological functions has come from the study of virus-host cell interactions. This fact is, in part, due to the ability of viruses to redirect key cellular processes away from their intended cellular functions towards building thousands of new virus particles comprised of relatively few components. These viral components are often produced in abundance, making the cellular processes that they influence easier to study than if one was investigating these processes in non-infected cells.***This application focuses on cellular processes that take place in normal cells but are also involved in the assembly of herpesviruses, a large group of viruses that infect animals ranging from mollusks to man. We use herpes simplex virus type 2 as a model system, however the processes under investigation are relevant to all viruses in this group. The initial stages of herpesvirus assembly take place in the cell nucleus where virus DNA is replicated and packaged into a protein shell called a capsid. DNA-containing capsids must exit the nucleus into the cell cytoplasm where final steps in virus assembly take place. This process is referred to as nuclear egress and requires the activities of numerous viral and cellular proteins including two key virus proteins called UL31 and UL34. We have discovered that the UL31 and UL34 proteins have the capacity to drive a remarkable reorganization of nuclear membrane structure. We hypothesize that this nuclear membrane reorganization is required for nuclear egress. Intriguingly, the nuclear membrane reorganization promoted by UL31 and UL34 closely resembles a poorly understood structure found in many normal cell types called the nucleoplasmic reticulum. The experiments described in this proposal will:***1) Describe the features of nuclear membrane reorganization using state-of-the-art imaging technologies.***2) Address the mechanisms by which UL31 and UL34 drive nuclear membrane reorganization.***3) Determine the significance of nuclear membrane reorganization on HSV-2 assembly.***It is anticipated that our findings will provide insight into the rules governing the trafficking of large protein complexes across membranes, the proliferation and remodeling of nuclear membranes and insights into the assembly and function of the nucleoplasmic reticulum. These findings will be important to researchers studying many aspects of cell biology and normal cell function by advancing our understanding of fundamental cellular processes. Furthermore, the performance of the studies described will provide HQP with hands on training in advanced imaging and leading edge molecular genetics techniques that will offer a powerful competitive edge to these individuals when they enter the academic, industrial, or biotechnology career sectors.