Figure 5.

The uORF2 REI permissiveness depends also on its own, eIF3-dependent, sequence-specific RPE v., which shares sequence similarity to uORF1-specific RPE i. Sequence alignment of uORF1-specific RPE i. with the newly identified uORF2-specific RPE v. schematically depicted with the post-termination 40S ribosome with the uORF2 stop codon residing in its A-site. The previously identified substitution of the uORF1-specific RPE ii. (CAAII) and a newly generated substitution of RPE v. (SUB18) were individually or in combination introduced into the uORF2-only construct and the resulting constructs were introduced into YSG2 and YSG15 strains and analyzed as described in Figure 2A.