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

Stimulation of translation across uORFs 2 and 3 by eIF3h is not dependent on the uORF peptide sequences. Two independent frameshift mutations were introduced into uORF2a/2b to change the sequence of the encoded peptide while retaining its native length and also the flanking sequences. For uORF3, point mutations were introduced to change three out of its five amino acids. The frameshift data (wild type versus eif3h) were statistically significant by paired t-test (P < 0.002).