Genetic analysis of murine hepatitis virus strain JHM

We performed a genetic analysis of 37 temperature-sensitive mutants of murine hepatitis virus strain JHM. Of our mutants, 32 did not induce murine hepatitis virus-specific RNA synthesis in infected cells at the restrictive temperature, 39 degrees C. By complementation testing we have identified at least seven nonoverlapping complementation groups. Six of the genes identified in this way are required for murine hepatitis virus-specific RNA synthesis. The seventh complementation group is made up of five mutants which induced virus-specific RNA synthesis at 39 degrees C.