Temperature-sensitive mutants of Chandipura virus. II. Phenotypic characteristics of the six complementation groups.

Fifty temperature-sensitive (ts) mutants of the rhabdovirus Chandipura virus have been classified into six complementation groups designated ChI to ChVI. Group ChI contains 44 mutants, group ChII contains 2 mutants, and the remaining groups have 1 mutant each. Mutants in groups ChI, ChIII, ChIV, and ChVI had RNA-negative phenotypes in experiments measuring amplification of RNA synthesis at restrictive temperature. The two mutants in group ChII had RNA-positive phenotypes, and the virions were thermolabile. Mutant ts Ch851 of group ChV was also RNA positive, and the M polypeptide of this mutant appeared to be unstable in cells incubated at restrictive temperature. It is likely, therefore, that complementation groups ChII and ChV represent the genes coding for the two viral proteins of the virion envelope. No precise assignment can be made in the case of the four RNA-negative groups, since all the mutants examined showed some polymerase activity in vitro at restrictive temperature. An attempt to obtain polymerase mutants by screening for sensitivity to rifampin was not successful. Six temperature-dependent host range mutants (the tdCE phenotype) of Chandipura virus failed to multiply in chicken embryo cells at restrictive temperature, but otherwise they differed in their host range properties from similar mutants of vesicular stomatitis virus.