STRUCTURE/FUNCTION OF VARICELLA ZOSTER VIRUS DNA.
RUYECHAN, WILLIAM T Principal Investigator
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Varicella zoster virus (VZV) is the causative agent of chicken pox and shingles. The overall objective of thisproposal is to understand the nature of physical and functional interactions between the complex VZV majortransactivator, IE62, and specific components of the cellular transcription apparatus. Such information is criticalto our understanding of the complex pathogenesis of VZV infection. It is particularly important in terms of thelive attenuated VZV vaccine. Vaccination is now recommended for all children and recently the FDA approvedthe vaccine for use in the elderly for the prevention of zoster based on an extensive clinical trial. Currently littleis known concerning attenuation of the vaccine virus. Since the IE62 gene accumulates the majority ofmutations in the attenuated vaccine strains, understanding its interaction with host functions could lead to thedevelopment of second generation vaccine whose molecular mechanism of attenuation is well understood.The work proposed involves three Specific Aims. Specific Aim 1: Functional Interaction of IE62 with CellularFactors. We will examine the functional interaction between the IE62 protein and two essential cellulartranscription factors the Mediator complex and HCF-1. This will be done by mapping and mutation ofinteracting domains and expression of these mutations in the context of the viral genome. Specific Aim 2: Roleof DNA Binding in the Mechanism of IE62 Activation. We will determine the specificity and affinity of the IE62-DNA Interaction and the effect of mutations in the DNA-binding domain on IE62 DNA-binding andtransactivation and viral gene expression. Specific Aim 3: Interrelationship Between IE62 Structure andFunction. We will mutate the IE62 SEAC domains and assess there function in in vitro transcription assays.The growth properties of virus carrying mutations in these domains will be determined. We will determine if thetwo transcriptional activation domains present in the IE62 homodimer are both required for IE62 function andwhat functions they perform. These studies will help us to understand the ways in which this important viralprotein influences the functions of cells following infection. Since the live attenuated VZV vaccine will be usedto prevent chicken pox and shingles throughout the U.S. population it is important to understand how the virusinteracts with its human host. This work should also result in information that could be used in strategies todevelop better anti-viral drugs and vaccines.