Genomic organization of the wild type poliovirus (Mahoney strain) and the Sabin live attenuated poliovirus vaccine

(Upper panel) Mahoney virus. P1 is the precursor of the capsid proteins; P2 and P3 are the precursors of the noncapsid proteins. The genome segment from nucleotide 743 to 3,832 encodes a polyprotein precursor amino acids 1 to 1,030. Noncoding region = NCR (also designed UTR for untranslated region); nuclotide = nt.

(Middle panel) Sabin OVP1 strain. The complete nucleotide sequence of the attenuated Sabin OPV1 compared with the WPV Mahoney strain (Nomoto et al 1982) identified 57 base substitutions to be scattered all over the genome. Of these, 21 were missense mutations (red triangle) resulting in amino acid changes in some viral proteins, especially in the NH2-terminal half of the VP1 capsid protein, involved in attenuation (each mutation indicated by a red star). The location of the principal nucleotide substitutions leading to the attenuated phenotype is indicated in blue (A480G, G935U, U2438A, G2795A, and C2879U for the Sabin OPV1).

(Lower panel) Location of the principal nucleotide substitutions leading to the attenuated phenotype of Sabin OPV2 and OPV3 (the other substitutions are not shown).

Abbreviations: NCR, noncoding region; nt, nucleotide; OPV1, OPV2, OPV3, oral live-attenuated poliovirus vaccine types 1, 2, and 3; P1, the precursor of the capsid proteins; P2 and P3, precursors of the non-capsid proteins (also designed UTR for untranslated region); WPV, wild poliovirus.

(Source: Devaux CA, Pontarotti P, Levasseur A, Colson P, Raoult D. Is it time to switch to a formulation other than the live attenuated poliovirus vaccine to prevent poliomyelitis? Front Public Health 2024;11:1284337. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Reference cited:
Nomoto A, Omata T, Toyoda H, et al. Complete nucleotide sequence of the attenuated poliovirus Sabin 1 strain genome. Proc Natl Acad Sci U S A 1982;79(19):5793-7.