Comparison of dengue viruses and some other flaviviruses by cDNA-RNA hybridization analysis and detection of a close relationship between dengue virus serotype 2 and Edge Hill virus.

Variable amounts of cDNA were synthesized in vitro from RNA extracted from several flaviviruses, including the four prototype dengue (DEN) virus serotypes. The synthesis was carried out using an oligo(dT) primer, suggesting the presence of a short poly(A) region at or near the 3' end of some flavivirus genomes. The DEN-1 and DEN-2 prototype strains produced the largest amount of cDNA and were therefore used to investigate further the relatedness of flavivirus genomes by cDNA-RNA hybridization. The flaviviruses studied are related to each other to some extent since the hybrids formed exhibited about 30% S1 nuclease resistance, but a closer relationship was detected between dengue viruses of serotype 1 and 4 and between dengue virus serotype 2 and Edge Hill virus. A monoclonal antibody to the envelope protein (V3) of dengue viruses reacted with Edge Hill virus, confirming the genetic relationship between the viruses.