In vitro coupled transcription and translation was performed using the TNTH Coupled Reticulocyte Lysate System (Promega) as per the manufacturer's instructions. Reactions were incubated at 30uC for 1-2 hr. For non-radiolabelled reactions the 35 S-Methionine was replaced with 1 mM unlabelled Methionine (2 ml). Reaction products (1-2 ml) were analysed by SDS-PAGE. Gels were stained and prepared for autoradiography by incubating for 30 min in a solution containing 32 g sodium salicylate, 100 ml methanol and 100 ml dH 2 O. Gels were dried under vacuum and the reaction products were detected by exposure to Kodak X-Omat scientific imaging film (Sigma) at 270uC for 16 hr followed by developing using a Kodak automated developer.