Comparison of the 5' and 3' untranslated genomic regions of virulent and attenuated foot-and-mouth disease viruses (strains O1 Campos and C3 Resende)

1 Zentrum für Molekulare Biologie Heidelberg (ZMBH), D-6900 Heidelberg, Germany 2 Pan American Foot-and-Mouth Disease Center, P.O. Box 589, 20001 Rio de Janeiro, Brazil and 3 Biochemisches Institut am Klinikum der Justus-Liebig-Universität, D-6300 Giessen, Germany The complete 5' and 3' non-coding regions of two attenuated South American foot-and-mouth disease virus (FMDV) vaccine strains, O 1 C-O/E and C 3 R-O/E, and their corresponding virulent parental strains, O 1 Campos and C 3 Resende, have been cloned from polymerase chain reaction-amplified primary cDNA. Differences observed in the derived nucleotide sequences between attenuated and virulent viruses seem not to affect regulatory signal structures, supporting the theory that genetic variations, primarily in the 3' halves of the viral genomes, contribute to the attenuation phenotype of the vaccine strains. In addition, this is the first report on the complete sequence of the 5' untranslated region of a C-type aphthovirus. Approximately 10% of the nucleotides differ from the corresponding known sequences of serotypes A or O. Received 23 January 1991; accepted 25 July 1991.