Fig. 4. Bipartite sequence complementarities of the potential ribosome binding sites. (A) Complementarities of the 3' hairpin of human 18S rRNA and the human adenovirus tripartite leader (3LDR, Ad, C1-C3). Nucleotide positions relative to the +1 start site of transcription are indicated (Yueh and Schneider, 2000). (B) Complementarities of the 3' hairpin of V. carteri 18S rRNA (Rausch et al., 1989) and three regions of the 5' UTR of regA from V. carteri f. nagariensis and V. carteri f. kawasakiensis (Duncan et al., 2006). E1.1 und E1.2 are located in the first exon; E2 is in the second exon (Intron 2 will not be spliced in comparison to nagariensis); and E3 in the third exon. Nucleotide positions relative to the +1 start site of transcription are indicated (Fig. 2).