Fig. 6: p18m-Gag interaction is critical for restriction activity.
a–f Protein extracts from galactose-induced yeast cells (Input) were fractionated over a 7–47% continuous sucrose gradient and immunoblotted. The bars below anti-TY blots denote peak Gag fractions containing more than 1/9 of the Gag signal across the gradient, as determined by densitometric analysis. A representative image of at least 3 replicates is shown. Strains used: DG4292 (a), DG3739 (b), DG4162 (c), DG4147 (d), DG4165 (e), DG4340 (f). Migration of molecular weight standards is shown alongside the immunoblots. Images of the whole gel immunoblots are provided in the Source Data file. g (Left) Schematic illustrating endogenously expressed, chromosomal Ty1 and galactose-inducible, plasmid-borne p18mAUG1. Ty1 is tagged with the his3-AI retromobility indicator gene; histidine prototrophy requires retromobility. (Right) Relative restriction by p18mAUG1 and p18mAUG1-A273V of Ty1 and Ty1-A273V for homotypic and heterotypic pairings. The relative restriction is calculated as the percentage of fold-restriction by the homotypic pairing. Quantitative mobility data is mean from four replicates of galactose-induced cells. Each bar represents the mean of the four independent measurements displayed as points. The error bar centre represents the mean of the four measurements and the error bar extent ± the standard deviation. Significance is calculated from a two-sided Student’s t-test compared with homotypic relative restriction (*p < 0.05, exact p-values provided in Supplementary Table 1). The cartoons below illustrate homotypic or heterotypic p18m-Gag interactions. See also Supplementary Table 1 and Supplementary Fig. 7. Source data is provided in the Source Data file.
