Molecular Characterization of the Segment 2 Gene of Epizootic Hemorrhagic Disease Virus Serotype 2: Gene Sequence and Genetic Diversity

Abstract

The complete nucleotide sequence of the gene encoding the major outer capsid protein VP2 from the Alberta isolate of epizootic hemorrhagic disease virus serotype 2 (EHDV-2) was determined. Complementary DNA (cDNA) corresponding to segment 2 was 3002 nucleotides in length with a single open reading frame that encoded a VP2 of 982 amino acids. Although the VP2 from EHDV-2 was only 34% homologous to the cognate protein from EHDV-1, their predicted hydropathic profiles were similar, suggesting that conservation of structure is important biologically to these capsid proteins. Sequence analysis of six North American EHDV-2 field isolates showed a high degree of comparative genetic identity (>97%). Phylogenetic profiles constructed suggest that regionalization of the viruses within the North American continent has contributed to the genetic diversity.