Fig. 6.

Growth phenotypes of pseudo-revertant and suppressor variants of CRS2 and CRS4. (a) Growth phenotypes of suppressor variants of mutant CRS2 are shown. Viral titres were measured by plaque assay (see Methods) at three different temperatures. The genotypes and the selection temperatures and phenotypes of the three suppressor variants are summarized in Fig. 7. (b) Growth phenotypes of the three suppressor variants of mutant CRS4 are shown. Plaques were picked and amplified at the temperatures indicated in Fig. 7 and the lysates were titrated by plaque assay at 33, 37 and 39.5 °C. Plaque pictures were taken from different dilutions, as indicated for each well.