The h subunit of eIF3 promotes reinitiation competence during translation of mRNAs harboring upstream open reading frames

Computer simulation of the translational defect in eif3h mutant plants. (A) Model parameters. (Gray boxes) ORFs. Spanning bars indicate the range over which a given term applies. (B–F) Distributions of parameter estimates. x-axis length reflects the manually set boundaries of possible parameter estimates. y-axis counts indicate the number of times out of 100 trials that a parameter fell into one of 20 x-axis bins. (B) Loss rate of reinitiation competence (k₁) as a function of uORF length (u [nt]). (C) Regaining of reinitiation competence (k₂) as a function of intercistronic spacer length (s [nt]). (D) Probability of AUG recognition in a strong context (p_cs). (E) AUG recognition in a weak context (p_cw). (F) Escape from attenuation upon translation of uORF2b peptide (p_2b). (G) Scatter plot illustrating the match between model output using MLEs (x-axis) and experimental data (y-axis, ± one standard error) for all 21 AtbZip11 5′ leader constructs in wild-type (dark green) and eif3h plants (red). (Light green symbols) Predicted expression values using model parameters culled from the literature (see Table 1).