Fig. 2.

Sensitivity of XMRV to human and mouse APOBEC3 proteins. LacZ-encoding XMRV or Mo-MLV viruses were produced in 293T cells transiently transfected with 0.5 μg HA-tagged APOBEC-expressing plasmid or empty vector. (A) Virus titers were measured by RT-ELISA and equivalent amounts of virus were used to challenge D17 cells. Productive infection was measured after 48 h as the induction of β-galactosidase activity, monitored using a chemiluminescent substrate. Results are given in counts per second and are representative of at least two independent experiments. (B) Whole-cell lysates were prepared from the 293T cells used above and expression of APOBEC proteins was confirmed by immunoblot analysis using a high-affinity anti-HA monoclonal antibody.