Localization of the ts defects of ts mutants of influenza A virus using complementation analysis and gel analysis of the RNA segments of recombinants

Abstract

Two sets of temperature-sensitive ( ts) mutants of influenza A virus (derived by mutagenesis of the Hong Kong (HK) and WSN strains, respectively) were analyzed for shared lesions using a complementation-recombination assay which was performed directly on tissue culture monolayers. Each of these sets had previously been shown to consist of seven complementation groups. By this assay three of the HK groups were shown to correspond to WSN complementation groups: HK group 1 and WSN I shared a common ts lesion as did HK group 5 and WSN group III; finally, HK group 6 and WSN group II were shown to be related. The relationship of the WSN groups IV, V, VI, and VII and HK groups 2, 3, 4, and 7 could not be interpreted from the complementation-recombination studies. We therefore sought to localize the lesions of the HK mutants by preparing ts + recombinants between the HK groups 6 and 7 mutants and PR8 wildtype or WSN ts mutant 51. In this way we have localized the lesions in these mutants to RNA segments 3 (P2) and 5 (NP), respectively. The findings with HK group 6 confirm the genetic analysis while those with HK group 7 suggest the occurrence of three independent groups of lesions on the NP segment of HK (groups 2, 3, and 7). The cotransfer of the NS segment with the NP and P2 genes is discussed, as are the factors which make genetic analysis by biological methods difficult, but perhaps useful in understanding the functional interactions of the influenza polypeptides.