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Team:Wageningen UR/Project
From 2012.igem.org
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Modification of Virus-Like-Particles
This year, the Wageningen UR team 2012 will work on the modification of virus-like particles (VLPs) to make them interesting platforms for vaccine production and/or site specific drug delivery. VLPs are empty virus capsids, meaning that they do not contain any viral genome, proteins and epitopes, except for the coat proteins. Coat proteins of some viruses have shown the ability to self-assemble in absence of its viral genome and other viral proteins, and thus form VLPs.
Introduction
The plan of our project is to use these VLPs to create a universal platform on which vaccines can be created or with which drugs can be delivered. To facilitate this, we want to put anchors on the outside of the VLP to attach antigens and ligands to, and anchors on the inside to attach medicine to, which is then encapsulated by the VLP. The anchors that we want to use are charged coils, which are already being used to encapsulate GFP into Cowpea Chlorotic Mottle Virus (CCMV) VLPs. This technique relies on charged coil peptides (negatively charged E-coil and positively charged K-coil) that can form ion bonds together. We want to use this technique to obtain a universal attachment system with which we can attach all kinds of epitopes to the VLP.
We selected 3 viruses that we want to use to produce VLPs with universal attachment units on the inside and outside of the VLPs. We have selected them based on existing experience at Wageningen University, increasing the probability of success and their promising structure. Besides CCMV, we will use the Hepatitis B core antigen VLP for the production of vaccines. The Potato Leaf Roll (PoLeRo) virus will be used to yield a newly expressed VLP in E. coli, because of its promising structure with outside spikes that are easy to modify. All three VLPs will be expressed in E. coli and all three will need to be submitted in the same standardised form for the competition. Therefore we will use the same E. coli strain for all three tracks. This increases the efficiency of the whole projects, because growing conditions will be the same.
Project description Team Wageningen_UR
Synthetic biological approach for the development of standardized medical delivery systems
Our team will join the competition with a medically focussed project on Virus-Like Particles (VLPs). VLPs are empty viruses that lack a genetic content, and can therefore not self-replicate. These VLPs can be modified to make vaccines or used as bio-nano carriers for site-specific drug delivery.
The development of conventional vaccines is slow, laborious and costly. VLPs can serve as a cheap and standardized platform for the development and production of vaccines, making preventive healthcare accessible worldwide. Three different viruses will serve as initial workhorses. Cowpea Chlorotic Mottle Virus (CCMV), Turnip Yellows Virus (TuYV) and Hepatitis B (HepB) have been selected for their promising properties in either packaging molecules or modification possibilities on the outside of the particle. The research done on these three VLPs should lead to one standardized tool.
Charged coils applied on the outside of the VLP will serve as a docking site in order to obtain one standardized tool for medical delivery systems. The epitope of interest is fused to the oppositely charged coil designed to connect to the docking site. With this, a Plug and Apply system is designed, creating the desired standardized platform.
Modification of the monomere can inhibit multimerization and with it formation of the VLP. Therefore, tertiary and quarternary protein structure modelling is used to predict whether the modification will inhibit assembly. If the in silico results are positive, the construct will be made and cloned in Escherichia coli.
Formation of VLPs is usually confirmed using Electron Microscopy (EM). This is rather time consuming and expensive, so Dynamic Light Scattering (DLS) is investigated as an alternative method. DLS can provide an indication of VLP formation but conclusive evidence should be obtained by EM.
The formation of the first VLP samples is confirmed by using these two detection methods, and the gene is standardized conform the rules of iGEM. This gene will now serve for further development of the standardized medical delivery systems, making mass development and production of new vaccines possible.
Project Description
