Figure 7.

Murine GFP-Mx1 localized to cytoplasmic structures in human Huh7 cells. Cultures of Huh7 cells in 35-mm plates were transiently transfected with the expression vector for murine GFP-Mx1. 2 days later, the cultures were fixed using 4% paraformaldehyde, permeabilized using the 0.05% Triton buffer, and stained with DAPI to visualize the nuclei and imaged using two-color fluorescence. In A, the left image shows two adjacent cells—one showing GFP-Mx1 exclusively in nuclear bodies and one cell with GFP-Mx1 present extensively in cytoplasmic filaments and cytoplasmic structures. Similarly, the right image in A shows adjacent cells—one with extensive cytoplasmic filaments and cytoplasmic bodies of GFP-Mx1—and part of a nucleus with only nuclear GFP-Mx1 bodies (bottom left). Approximately 20–30% of transfected cells showed cytoplasmic murine GFP-Mx1 (also see Fig. S2). B summarizes a three-color immunofluorescence analysis of the cytoplasmic GFP-Mx1 filamentous structures for intermediate filaments (using the anti-giantin pAb). Red and green pixel fluorescence was measured along the white line in the merged image in B, and the data are summarized in the plot to the right of the image. Arrows in the plot indicate colocalization of red and green filaments. Scale bars, 10 μm.