Fig. 4.

HuCTR1 promotes binding of CERV2 particles to CHO cells. (A) Images of CERV2 particles bound to CHO cells or a derivative expressing huCTR1, as indicated. A single image representing a projection of a z-series of fluorescent images that capture the entire thickness of the cell monolayer is shown (Left), and a merge of fluorescence and phase-contrast images is also shown (Right). (B) Quantitation of the number of MLV Gag-GFP particles with (circles) or without (triangles) CERV2 Env protein that bound to CHO or CHO-huCTR1 cells, as indicated. Particles were incubated with cells in the absence (open symbols) or presence (filled symbols) of CuCl₂. For quantitation, 15 individual cells under each condition were chosen at random and the number of GFP particles per cell was counted. Each symbol represents an individual cell and the mean number of particles per cell is indicated by a horizontal line. P values were calculated using the unpaired, two-tailed t test (Graphpad Prism).