Poxviruses, and in particular vaccinia virus, have been utilized as systems for the expression of proteins in eukaryotic cells. The capacity to incorporate large amounts of DNA coupled with their wide host range allows for the expression and correct processing of a great variety of proteins in many cell lines. We have developed a conditionally lethal vaccinia virus which expresses the T7 bacteriophage RNA polymerase. Under the restrictive conditions of elevated temperature the virus undergoes an abortive infection where greatly reduced amounts of the late or post-replicative genes are synthesized. We are presently quantitating the absolute level of expression of foriegn genes in this system and comparing its utility to presently available vaccinia T7 expression systems. A new set of direct ligation vectors has been constructed and characterized which provide a set of universally applicable direct ligation poxviruses cloning vectors extending the utility of poxvirus vectors for construction and expression of complex libraries. One strategy for vaccine development is the enhanced expression of a pathogens gene in a nonpathogenic vector which can be subsequently introduced into a host. Poxvirus vectors are commonly used as nonpathogenic expression vehicles. This research project investigates potential strategies for the efficient construction of poxvirus vectors and the efficient production of foreign proteins by a hybrid vaccinia virus. The development and use of novel construction and expression strategies is being utilized in poxvirus research to optimize their utility as vaccines. My review responsibilities are dedicated to the critique of proposals using poxvirus vectors and this project aids in my ability to critically review such proposals.
