Temperature-sensitive mutants of Chandipura virus. I. Inter- and intragroup complementation.

Fifty temperature-sensitive (ts) mutants of Chandipura virus, a human rhabdovirus, have been classified into six complementation groups, designated ChI, ChII, ChII, ChIV, ChV, and ChVI and containing 44, 2, 1, 1, 1, and 1 mutants, respectively. Weak complementation was observed within group ChI, allowing the division of the group into subgroups ChIA and ChIB. Intragroup complementation was most extensive within subgroup ChIB, and one mutant in this subgroup complemented all but one (ts Ch598) of the mutants in group ChI. If ts Ch598 had been omitted from the analysis the number of complementation groups would have been increased to seven. Consequently, in circumstances where intragenic and intergenic complementation cannot be clearly distinguished, the number of complementation groups identified in rhabdoviruses could be overestimated. The identification of six complementation groups in three different rhabdoviruses need not imply the existence of an as yet unidentified sixth virus-specified polypeptide. The extensive intragroup complementation observed in Chandipura virus suggests that the functional form of one at least of the virion proteins of Chandipura virus is a multimer.