FIG 6.

Mutations in μ1 hyperstabilize T3D. (A) ISVPs (2 × 10¹¹ particles/ml) of T3D and T3D with the indicated M2 mutations were divided into aliquots of equivalent volume and incubated at either 4°C or over a range of temperatures (32 to 46°C) for 20 min. The reaction mixtures were chilled on ice and digested with 0.10 mg/ml trypsin for 30 min. Following addition of loading dye, the samples were subjected to SDS-PAGE analysis. The gels shown are representative of at least 3 independent experiments. The positions of major capsid proteins are shown. μ1 runs as μ1C. (B) ISVPs generated from purified virions were divided into aliquots of equivalent volume and incubated at either 4°C or 49°C for 20 min. Reaction mixtures were then diluted in PBS and subjected to plaque assay. The data are plotted as mean loss of infectivity for three independent samples in comparison to samples incubated at 4°C. Error bars indicate SD. ***, P < 0.001, in comparison to T3D, as determined by Student’s t test.