FIG. 3.

Alignment of C. elegans SLs. The sequences of the C. elegans trans-spliced leaders that have been identified are shown (10, 34). In some cases, SL RNA genes contain identical leader sequences but divergent sequences corresponding to the rest of the RNA (for example, SL genes encoded by the SL2 α and β genes, as well as SL genes encoded within the cosmids C17C3 and ZK1248, have identical leader sequences [10, 16, 34]). Gaps (indicated by dashes) are positioned in the alignment to maximize the degree of identity between the leaders. The consensus sequence for the leaders is shown at the bottom; the AG dinucleotide is also highly conserved in C. elegans cis-splice donor sites (17).