Grant: Project Grant

Poxviruses are big DNA viruses that infect many different creatures including humans. The most well known is variola virus, which causes smallpox, and the poxvirus most commonly studied in laboratories is vaccinia virus. Forty years ago vaccinia virus was used as a vaccine to eradicate smallpox. Although no longer commonly used for that original purpose, recombinant forms of vaccinia virus are still used to vaccinate against other diseases like malaria. More complex genetic modifications have also been introduced into vaccinia with the goal of producing forms of virus that will selectively kill cancer cells. These are called "oncolytic" viruses. My laboratory has a long history of studying the linked processes of poxvirus replication and genetic recombination. (Replication makes copies of the virus, recombination rearranges the DNA in a virus genome.) Our basic research has produced a popular commercial recombination-based cloning technology ("InFusion"), contracts to help develop smallpox antivirals and new vaccines, an oncolytic virus targeted for Phase I trials in 2019, and a new method for producing recombinant poxviruses from "scratch" using synthetic DNA. All of these translational activities require an understanding of how poxviruses recombine DNA and all are enhanced if we can optimize the rapid production of properly assembled recombinants. To this end we plan to study three aspects of poxvirus replication and recombination. First, we'd like to gain a better understanding of how the cell in which vaccinia replicates affects production of recombinant viruses. Second, we've discovered a new way of making synthetic recombinant viruses and will use it study how virus genomes are constructed. Third, our new technology also provides a tool for exploring how smallpox vaccines might have evolved over time from a horsepox virus-like ancestor. This will provide ways to improve the safety of these vaccines and other vaccinia-based biotherapeutics.