Fig. 7. Schematic representation of the Endo16 promoter in S. purpuratus (A) and L. variegatus (B). The LvEndo16 promoter sequence indicates only those binding sites identified in module A of S. purpuratus. Results from transient expression assays indicate that additional binding sites required for LvEndo16 expression are likely to occur in the 2.2 kb region, but have not yet been identified. (An asterisk indicates that a nucleotide substitution or indel occurs within a binding site compared to the Endo16 promoter sequence in S. purpuratus.) A dot plot (C) and feature maps (D-F) were generated by FamilyRelations based on a seqcomp analysis of the Endo16 promoter (Brown et al., 2002). Alignment of the SpEndo16 and LvEndo16 promoter sequences is noted in the upper right corner of a dot plot (C), corresponding to module A. This is also evident at the right of a feature map (D). In neither case is there convincing evidence for sequence similarity upstream of module A. This result is supported by pairwise comparisons of the Endo16 promoter sequence with BAC sequence from the opposite species. Only one region of conservation corresponding to module A is detected in a pairwise comparison of the SpEndo16 promoter sequence and a BAC sequence from L. variegatus that contains the LvEndo16 locus (E). The reciprocal analysis revealed two regions of conservation, corresponding to module A as well as a microsatellite consisting of TAC repeats (F).