The effects of p12 mutations in different gammaretroviruses. (A) An alignment of the p12 sequence from various gammaretroviruses is shown. Shaded boxes indicate the position of each p12 mutant in each species and colours correspond to the bar colours in the graphs below. As GaLV has a small N- terminal region, the mutant TDDLL/AAAAA has been named GaLV N (G). (B-G) LacZ-encoding wild type or mutant VLPs were produced for each species of gammaretrovirus and equivalent RT-units of VLPs were used to challenge D17 cells. Infectivity was measured by detection of β–galactosidase activity in a chemiluminescent reporter assay. Results are plotted as the percentage of infectivity compared to the infectivity of the corresponding wild type VLPs for each species. The mean and range of three independent experiments are shown.