%0 Journal Article %A Cox, Nancy J. %A Kendal, Alan P. %A Shilov, Alexander A. %A Alexandrova, Galina I. %A Ghendon, Yuri Z. %A Klimov, Alexander I. %T Comparative Studies of A/Leningrad/134/57 Wild-type and 47-times Passaged Cold-adapted Mutant Influenza Viruses: Oligonucleotide Mapping and RNA–RNA Hybridization Studies %D 1985 %J Journal of General Virology, %V 66 %N 8 %P 1697-1704 %@ 1465-2099 %R https://doi.org/10.1099/0022-1317-66-8-1697 %K vaccine %K influenza A virus %K mutations %I Microbiology Society, %X SUMMARY Direct biochemical evidence for the existence of mutations in five of the RNA segments of the A/Leningrad/134/57 cold-adapted 47th passage mutant as compared with its wild-type progenitor has been obtained using two techniques. T1 oligonucleotide mapping of total viral RNA as well as of individual RNA segments revealed changes in RNAs 4, 5 and 6. Analysis of S1 nuclease-treated RNA–RNA hybrids on polyacrylamide gels revealed changes in at least one of the polymerase genes as well as in RNAs 4, 5, 6 and 7. These findings provide a direct demonstration for the existence of multiple mutations in the cold-adapted mutant vaccine strain. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-66-8-1697