Splicing and mouse-human conservation patterns for sense and antisense ESTs from UniGene cluster Hs.125819. The graph depicts the exon-intron splicing structures of transcript sequences belonging to UniGene cluster Hs.125819. Organization of figure as for Figure 2. Note that the BOU mRNA (GenBank accession NM_014473) is in this case oriented from right to left with respect to genomic contig Hs5_6844_24 of the NCBI human genome assembly. The mRNA encodes a putative dimethyladenosine transferase. Notably, however, there appear to be two potential termini for the antisense ESTs (which are oriented from left to right), suggesting that we are observing either alternative termini of a single transcript or two distinct antisense RNA species. One terminus is coincident with an island of mouse-human conservation within the 3' UTR of the sense transcript. The second is coincident with the last internal coding exon of the sense transcript. In both cases, the sequence near each putative terminus contains an appropriately located polyadenylation signal. The antisense ESTs have no significant protein homologies, and do not appear to be spliced. However, the ESTs that we are observing may represent only the 3' terminus of a larger coding transcript. Notably, the islands of conservation immediately 'upstream' of the antisense ESTs also have no protein homologies, suggesting that this may not be the case.