Figure 2.

Yeast lethal phenotype induced by the selected integrase mutants. Drop tests: the INs described in Table 1 were expressed in the diploid AB2 yeast strain under minimal IN expression (5.6% glucose) on solid YNB media lacking leucine in order to perform the lethality test. Photographs were taken after incubating yeast cells for 3 days at 28°C. AB2 (WT IN) expressing the wild-type integrase and AB2 (C) expressing no integrase were used as controls. Percentages given for the ‘drop test’ experiments correspond to the yeast cell survival rates in the absence of integrase (C) or in the presence of wild-type integrase (WT IN) or the mutated integrase as indicated. The yeast cell survival rates were evaluated as described in Materials and Methods. The survival rates, measured as described in Materials and Methods, are shown in the figure.