Figure 1

Schematic view of EST-based polyadenylation site identification. Each UTR is aligned onto the complete EST database. A poly(A) site is validated when at least two ESTs match this site while respecting specific length, position and quality criteria (see Methods). The -300/+300 nt fragment surrounding each site (here called "terminal sequence") is then extracted for further analysis. For sites located near the 3' end of the UTR, we use the corresponding genomic sequence to complete the terminal sequence.