Determination of the 5' and 3' terminal noncoding sequences of the bi-segmented genome of the avibirnavirus infectious bursal disease virus

Terminal sequences of the bi-segmented dsRNA genome of 3 different strains of infectious bursal disease virus (IBDV) were analyzed by the rapid amplification of cDNA 5' ends (5'RACE) procedure. Both segments are 85% homologous in a 32-nucleotide sequence comprising the 5' end, whereas the 3' end has a conserved pentamer. Comparison to published terminal sequences of other IBDV strains revealed high conservation between the two segments but more serotype-specific nucleotide changes (5 on segment A and 3 on segment B) in the 5' noncoding region compared to the 3' noncoding region (none on segment A and 1 on segment B).