Fig.4.

Limits of multigene expression by baculovirus co-infection. Infection of Sf9 cells with one or two baculoviruses (expressing dsRed protein or EGFP, respectively) 48 h post-infection are shown. (A) Micrographs of the same field of Sf9 cells showing specific fluorescence signals for dsRed (left), and for EGFP (middle) and an overlay of the two (right). Multiplicity of infection (MOI) was one for both viruses. Cells that express dsRed are colored red, cells expressing EGFP are colored green. Cells that effectively co-express both dsRed and EGFP appear yellow in the overlay. (B) The influence of virus titers on co-expression efficacy was analyzed, and the results are shown in a graphical representation. The green, red and yellow bars represent the proportion of cells that expressed dsRed, EGFP or both dsRed and EGFP, respectively. At least 1500 cells in each condition were analyzed. Saturating co-infection with both viruses was not achieved in this experiment.