Research in Dr. Whitt's laboratory is directed towards understanding the requirements for the replication and assembly of the enveloped, nonsegmented negative-stranded RNA virus, vesicular stomatitis virus (VSV). VSV has proven to be a good model system for studying both virus replication and virus assembly because it is a relatively simple virus. It consists of a bullet-shaped virion composed of five viral proteins, a single molecule of negative-sense RNA, and a lipid envelope derived from the host cell plasma membrane which contains the envelope spike glycoprotein. The glycoprotein (G protein) of VSV is responsible for the attachment and entry of VSV into a susceptible host cell and is therefore essential for virus infectivity.
To identify and dissect the signals required for the replication and assembly of VSV Dr. Whitt has developed a "reverse genetics" system in which the G protein of VSV has been deleted (rVSV-deltaG). rVSV-deltaG has been used to produce VSV pseudotypes containing the envelope glycoproteins of heterologous viruses including viruses that require high-level containment. Since the infectivity of rVSV-deltaG is restricted to a single round of replication, analyses of viral entry can be performed using just biosafety level 2 (BSL-2) containment.