Functional formation of domain V of the poliovirus noncoding region: significance of unpaired bases.
Previously we have shown that polioviruses with mutations that disrupt the predicted secondary structure of the 5' noncoding region of domain V are temperature sensitive for growth. Non-temperature-sensitive revertant viruses had mutations that re-formed secondary structure by a direct back mutation of changes in the opposite strand. We mutated unpaired regions and selected revertants of viruses with single base deletions, where no obvious back mutation was available in order to gain information on secondary structure. Results indicated that conservation of length of a three base loop between two double-stranded stems was essential for a functional domain V to form. The requirement for the unpaired "hinge" base at 484 which is implicated in the attenuation of Sabin 2 was also confirmed. Results also underline the necessity for functional folding over local secondary structure stability.
Rowe
A
A
Division of Virology, National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Potters Bar, Herts, EN6 3QG, United Kingdom. arowe@nimr.mrc.ac.uk
Burlison
J
J
Macadam
A J
AJ
Minor
P D
PD
D020121:5' Untranslated Regions / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D017955:Poliovirus / Q000737:chemistry / Q000235:genetics* / Q000502:physiology*; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics; D013696:Temperature
D020121:5' Untranslated Regions; D012367:RNA, Viral