Temperature-sensitive mutants of influenza A/Udorn/72 (H3N2) virus II. Genetic analysis and demonstration of intrasegmental complementation

Shimizu, Kazufumi; Mullinix, Mary G.; Chanock, Robert M.; Murphy, Brian R.

doi:10.1016/0042-6822(82)90506-2

Cited by 24 publications

(18 citation statements)

References 52 publications

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“…In this paper we have analysed the defects exhibited by six ts mutants of A/Udorn/72 (H3N2) virus, all belonging to recombination group A, which has a mutation(s) in the PB2 gene segment (Shimizu et al, 1982b). It was shown that the thermostability of the virion RNA polymerase of all these mutants was decreased (Table 3).…”

Section: Discussionmentioning

confidence: 99%

“…), synthesis ofvRNA as well as cRNA from all segments begins simultaneously, the cRNA levels for all segments immediately reaching a low plateau, whereas the vRNA levels steadily increase. The syn-0001-0317 © 1991 SGM * The complementation index was defined as the ratio of the number of plaques observed at 40 °C to the expected number of cells infected with the two viruses, as described previously (Shimizu et al, 1982b). thesis of mRNAs encoding the late proteins starts with the increase in cRNAs and vRNAs.…”

Section: Introductionmentioning

confidence: 99%

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Involvement of the influenza A virus PB2 protein in the regulation of viral gene expression

Mukaigawa

Hatada

Fukuda

et al. 1991

Journal of General Virology

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To determine the function(s) of the PB2 protein of influenza A virus, six temperature-sensitive (ts) mutants of A/Udorn/72 (H3N2) virus, each carrying a ts mutation in the PB2 gene, were analysed for virus RNA and protein synthesis. One of the mutants, ICRC27, exhibited unique phenotypes and was characterized in detail. At the non-permissive temperature, 40 °C, the accumulation of mRNA for each genome segment was reduced severely, leading to delayed and reduced synthesis of viral proteins, complementary and viral RNAs (cRNAs and vRNAs). At the permissive temperature, 34 °C, the mutant virus produced severalfold greater concentrations of both mRNAs and cRNAs of PB2, PB1 and PA segments than wild-type virus. The synthesis of the three polymerase proteins and the induction of RNA polymerase activity were also greatly increased. By contrast, the expression of the haemagglutinin (HA) gene was severely suppressed. The over-production of the polymerase mRNAs was not observed during primary transcription, i.e. in the presence of cycloheximide. The ts ÷ revertants oflCRC27 did not exhibit the ts defects and also lost most of the non-ts phenotypes at 34 °C. These observations indicate that the PB2 protein participates not only in the synthesis of viral RNAs, but also in the regulation of viral gene expression, i.e. in the downregulation of the three polymerase genes and the upregulation of the HA gene during secondary transcription.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Involvement of the influenza A virus PB2 protein in the regulation of viral gene expression

Mukaigawa

Hatada

Fukuda

et al. 1991

Journal of General Virology

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“…rV94(15C)/460A/Δ1724 and rV94(15C)/ 460P/Δ1724 were at least 10,000-fold restricted in replication at 39°C but replicated like wild type rHPIV2 in vivo (in an experimental animal with a body temperature of 38.6°C), suggesting that their ts phenotype was host-dependent, i.e., they were ts in LLC-MK2 cells in culture but not in vivo in respiratory epithelium. Such mutants have been described for other viruses [49]. This reversal of phenotype was also seen when a pair of ts att mutations in the L polymerase (at amino acid residues 992 and 1558) of HPIV3 were combined in one virus.…”

Section: Discussionmentioning

confidence: 62%

Recombinant human parainfluenza virus type 2 vaccine candidates containing a 3′ genomic promoter mutation and L polymerase mutations are attenuated and protective in non-human primates

Nolan

Skiadopoulos

Bradley

et al. 2007

Vaccine

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Previously, we identified several attenuating mutations in the L polymerase protein of human parainfluenza virus type 2 (HPIV2) and genetically stabilized those mutations using reverse genetics (Nolan et al., 2005). Here we describe the discovery of an attenuating mutation at nucleotide 15 (15 T→C ) in the 3′ genomic promoter that was also present in the previously characterized mutants. We evaluated the properties of this promoter mutation alone and in various combinations with the L polymerase mutations. Amino acid substitutions at L protein positions 460 (460A or 460P) or 948 (948L), or deletion of amino acids 1724 and 1725 (Δ1724), each conferred a temperature sensitivity (ts) phenotype whereas the 15 T→C mutation did not. The 460A and 948L mutations each contributed to restricted replication in the lower respiratory tract of African green monkeys, but the Δ1724 mutation increased attenuation only in certain combinations with other mutations. We constructed two highly attenuated viruses, rV94(15C)/460A/948L and rV94(15C)/948L/Δ1724, that were immunogenic and protective against challenge with wild-type HPIV2 in African green monkeys and, therefore, appear to be suitable for evaluation in humans.

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“…The plaques obtained at 40 °C after double infection with ts 1/93 and, for example, ts 1 can be cloned at least three times at 40 °C. This indicates that plaque formation at 40 °C is not due to intracistronic complementation (Heller & Scholtissek, 1980;Thierry et al, 1980;Shimizu et al, 1982). The reversion rates to wild-type of ts 1/93 and ts 1/1 are about 1/105.…”

Section: Undiluted Passage Mutants With Defects In Rna Segments 3 Andmentioning

confidence: 69%

Temperature-sensitive Mutants of Fowl Plague Virus (Influenza A) Generated by Undiluted Passages at 33 C

Scholtissek

Müller

1983

Journal of General Virology

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SUMMARYTemperature-sensitive (ts) mutants obtained by undiluted passages of fowl plague virus at 33 °C have their defects located mainly in RNA segments 3, 4 and 8 as determined by rescue to wild-type with standard ts mutants. This result is different from that obtained after treatment of virus with mutagens, where the frequency of mutations follows roughly the target size of the RNA segments. Many isolates generated after undiluted passages at 33 °C, which seem to have mutations in RNA segments 3 and 4, can be rescued to wild-type. This occurs, however, with certain defined standard ts mutants having a defect in RNA segment 4, but not by other segment 4 mutants. One such mutant, ts 1/93 (ts defect in segment 3), interferes with the multiplication of ts 227 (ts defect in segment 4) at the permissive temperature, presumably at the level of vRNA synthesis, preventing reassortment to wild-type. Similarly, ts 263 (ts defect in segment 3) interferes with the multiplication of ts 1/1 (ts defect in segment 4). For other such interfering mutants, the mechanism preventing reassortment to wild-type is different from that of ts 1/93 or ts 1/1, but is not yet understood. Thus, the number of mutations as determined by rescue with standard ts

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Temperature-sensitive mutants of influenza A/Udorn/72 (H3N2) virus II. Genetic analysis and demonstration of intrasegmental complementation

Cited by 24 publications

References 52 publications

Involvement of the influenza A virus PB2 protein in the regulation of viral gene expression

Involvement of the influenza A virus PB2 protein in the regulation of viral gene expression

Recombinant human parainfluenza virus type 2 vaccine candidates containing a 3′ genomic promoter mutation and L polymerase mutations are attenuated and protective in non-human primates

Temperature-sensitive Mutants of Fowl Plague Virus (Influenza A) Generated by Undiluted Passages at 33 C

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