FIGURE 7.

RNAMotif pattern matches to tRNA descriptors of different levels of stringency within 5′-UTR human sequences. Using the eukaryote tRNA descriptor of Tsui et al. (2003) without introns, the number of pattern matches is shown as a percentage of the total number of UTRs in either UTRdb, RefSeq, fully reviewed UTRs in RefSeq, or published IRES from eukaryote transcripts in Table 1 (see data sets in Fig. 1). The first pattern is strict because of the specific sequences required in the pattern matches as well as the overall tRNA structure. The second pattern only requires two of the eight specific base sequences that are standard in tRNAs as well as a maximal −10.0 kCal/mol free energy cut-off for the putative matching RNA structure as calculated by the efn2 program included with RNAMotif software. The last pattern is the same as the second pattern but does not have a free energy cutoff.