In vitro translations were carried out in nuclease treated rabbit reticulocyte lysate (RRL) (Promega). The amount of mRNA was 0.025 pmol and different amounts of oligonucleotides (0.025-15.625 pmol) were mixed with template for 20 min at room temperature. After incubation, 4 ml of RRL, 0.01 mM amino acids mixture except methionine, 2 mCi of 35 S methionine (10 mCi/ml, MP Biomedicals, in vitro translational grade) were added in total volume of 10 ml and incubated at 28 C for 1 h. After translation, samples were mixed with 2Â Laemmli buffer, boiled at 90 C for 5 min and resolved by 13% SDS polyacrylamide gels. Gels were fixed in 10% acetic acid and 30% methanol for 20 min, dried under vacuum, and exposed to phosphoimager screens (Biorad). The screen was scanned and the 0 frame and À1 frameshift protein products were quantified by Quantity One software (Biorad). Frameshift percentages were calculated by dividing the amount of À1 frameshift product by the amount of 0-frame and À1 frameshift products after correction for the number of methionines in the protein sequence, multiplied by 100.