-To determine the role of herpesvirus glycoproteins in viral neurotropism.
-To examine the role of other viral proteins involved in penetration, propagation or persistence in the nervous system.
-To undertake a structural study of selected herpes proteins involved in neurotropism.
We propose to elucidate which viral functions are necessary for alphaherpesviruses to penetrate and propagate in the nervous system. We plan to address this question both in vitro, in polarised cells and in primary cultures of neurons, and in vivo in suitable animal models, using appropriate mutants in which the gene of interest will be deleted. Our first objective will be to analyse the role of the external proteins of HSV1, PrV and VZV virons in the viral neurotropism. Our previous work has led to a better understanding on the role of five of the eleven herpes glycoproteins. We now plan to examine the role of the six other glycoproteins, by comparing the neurotropism of deletion mutants with that of wild type or rescued viruses, after intranasal inoculation of mice.
In addition to envelope glycoproteins, we will also examine other viral proteins which could play a role in neurotropism. Proteins UL 3.5 and UL 20 of PrV have been demonstrated to be involved in the egress of virions from the nucleus to the cytoplasmic membrane. Since this process is poorly understood in neurons but is important for transneuronal spread, respective mutant viruses will be analysed in vitro and in vivo. Protein IE63 of VZV is expressed in large amount during latency in neurons of rat and man. It is also expressed during productive infection in cell cultures, in the skin during zoster and in sensory ganglia during reactivation. Hence its exact role is unclear. Using transient expression assays, it has been shown that IE63 inhibits indirectly the expression of "immediate early" (IE) genes by decreasing the activity of an activating protein. This protein probably plays an important role in VZV latency and reactivation and its exact role will be investigated.
Finally, we propose to undertake a structural study of selected herpes proteins which have been involved in specific interactions with the host cell. Here we propose to study the major attachment proteins of PrV, gB and gC, and protein IE63 of VZV. If enough protein in its native configuration can be obtained from suitable expression systems, crystallisation will be attempted.
Funding SchemeCSC - Cost-sharing contracts
17498 Insel Riems
CB2 1QP Cambridge