FIG. 4.
Leader-body junctions in WBV subgenomic RNAs. Shown are the junction sites between a short sequence, called leader, that is derived from the 5′ end of the genome, and the coding (so-called body) sequences of subgenomic RNAs 2 to 4. The gray box highlights a sequence, CA(G/A)CACUAC, and its negative-strand complement that we predict to act as a core TRS element in WBV. As in corona- and arteriviruses (37, 47), this leader sequence is conserved near the 5′ end of the genome (nts 44 to 52) and upstream of the translation start codon of each of the downstream ORFs specifying the viral structural proteins, S, M, and N. For each of the core TRS elements, the flanking sequences in the WBV genome RNA and the corresponding minus-strand sequence are given. Possible base-pairing interactions between the minus strand and the proposed leader TRS are indicated, and the leader-body (L-B) junction in the respective mRNA, as determined by RT-PCR and sequencing, is given below. Sequences derived from the 5′ end of the genome (leader sequence) are boldfaced and underlined. Translation start codons of the S (RNA 2), M (RNA 3), and N (RNA 4) genes are boldfaced and italicized. Please note that, with respect to the minus-strand sequence, the actual fusion appears to occur slightly downstream of the fully complementary sequence rather than within this particular sequence.