Figure 4.
Activities of eIF1, IF3, IF3-CTD and YciH in dissociating aberrant eukaryotic 48S complexes. (A) Sequences of 5′-UTRs of β-globin mRNA and (CAA)n-GUS mRNA derivatives with initiation codons in bold. (B–F) Toe-printing analysis of 48S complexes assembled on mRNAs as indicated. Reaction mixtures contained 40S subunits, Met-tRNAiMet and factors as indicated. The positions of toe-prints caused by assembled 48S complexes are shown on the left. Full-length cDNAs are labeled. (E) ‘Complex I' indicates the position of toe-prints caused by ribosomal complexes whose leading edge was 21–24 nt. from the 5′-end of β-globin mRNA. (B, C) Lanes marked C, T, A and G show cDNA sequences derived using the same primer as that for toe-printing.