Rhabdoviruses includes many important human, animal and plant pathogens, including Rabies virus. Vesicular stomatitis virus (VSV) is a prototypic virus in the Rhabdoviridae, and it is a focus of the Whittaker Lab. Using the information provided by the recent crystal structure of the VSV glycoprotein (G), we are carrying out a mutagenesis study to determine the critical amino acids within the fusion domain of VSV G, as well as a related fish rhabdovirus, viral hemorrhagic septicemia virus (VHSV).