Figure 2

Extra copies of sup45-sl23^tsimprove growth of the strain 33G-D373-rSL23 carrying the chromosomal sup45-sl23^tsmutation at 37°C (A), but do not influence nonsense codon readthrough (B). Empty vector, YEplac181; multi-sup45-sl23, YEplac181-sup45-sl23. Photos were taken after incubation of transformants on leucine omission medium for 4 days. The strain 33G-D373-rSL23 carrying the plasmids indicated above, was transformed with either one of the pUKC815, 817, 818, 819 plasmids and grown in medium selective for plasmids to mid log phase. Then appropriate aliquots of yeast culture were taken and β-galactosidase activity was assayed. Suppression efficiency (average from three independent transformants, each in three parallels) was estimated as described [44].