Bioreg Discussion Paper
March 7, 2003
Wilson et al. (2000) Cell 102, 511-520.
1. How does the method of toeprinting work? What conditions need to be fulfilled to obtain a usable toeprint?
2. The eIF2-GTP/Met-tRNAi ternary complex is used in translation initiation. What is its counterpart that is used in the elongation phase of translation?
3. What was the significance of the failure of edeine to inhibit binding of 40S ribosomal subunits to the IGR-IRES (Figure 2A)?
4. What was the criterion used to decide what triplet was in the P site of 40S ribosomal subunits bound to IGR-IRES? (Figure 2)
5. What was the major conclusion from the combined data of Figure 2A - D of this paper.?
6. What was the significance of the finding that IGR-IRES could bind 80S ribosomes in the presence of GMP-PNP (Figure 3)?
7. What was revealed by amino acid sequencing of the translation products initiated at the IGR-IRES and variant versions of it?
8. In the IGRmut17 experiment (Figures 4B and C) , what would have happened experimentally if the P site did decode the IGRmut17 triplet (a stop codon) in the P site?
9. How valid is the precise positioning inferred from the toeprints of Figure 5? What other interpretations are possible?
10. What is the major change in thinking about translational initiation that comes from the results in this paper?
11. What might be the physiological function of initiation of translation of cellular genes by the mechanism proposed in this paper?