title: The formation of arenaviruses that are genetically diploid.
abstract: Analyses of RNA extracted from preparations of arenaviruses indicate that the relative molar proportions of the genomic L and S RNA species are frequently far from equal. In order to investigate the genetic significance of this observation temperature-sensitive (ts) mutants of two lymphocytic choriomeningitis (LCM) virus strains (ARM and WE) have been recovered and categorized into recombination groups (Groups I and II). Fingerprint analyses of wild-type progeny viruses obtained from dual infections with ARM Group II and WE Group I ts viruses indicate that they have L/S RNA genotypes of WE/ARM. It is concluded that the ARM Group II ts viruses have mutations in their L RNA species and that the WE Group I ts viruses have mutations in their S RNA species. Correspondingly it is deduced that the ARM Group I ts viruses have S RNA mutations and the WE Group II ts viruses mutations in their L RNA species. Cells coinfected with certain WE Group I mutants, or an ARM Group I and certain WE Group I ts mutants, have also yielded wild-type viruses. Fingerprint analyses have shown that the wild-type viruses obtained from the latter crosses are diploid with respect to their S RNA species. On subsequent passage these wild-type viruses shed high proportions of ts mutants. We interpret the data to indicate that the original Group I ts mutants that yielded the diploid viruses have mutations in different S RNA gene products so that the progeny produce plaques at the nonpermissive temperature by gene product complementation. No wild-type recombinant viruses have been obtained from crosses involving Pichinde and LCM ts mutants.
mesh_terms: D006477:Arenaviruses, New World / Q000235:genetics; D005814:Genes, Viral; D005816:Genetic Complementation Test; D005838:Genotype; D008217:Lymphocytic choriomeningitis virus / Q000235:genetics*; D009154:Mutation; D012313:RNA / Q000032:analysis / Q000235:genetics*; D012367:RNA, Viral / Q000032:analysis / Q000235:genetics*; D011995:Recombination, Genetic; D013696:Temperature
chemical_list: D012367:RNA, Viral; D012313:RNA