Figure 3.

The corona virus-infected cell. (a) A confocal microscope image shows the infection of primary cells by coronaviruses. Viral proteins are shown in red and nucleolar fibrillarin is shown in green. Most viral proteins remain in the cytoplasm, although nucleoprotein can localize to the nucleolus and redistribute fibrillarin. Studies of coronavirus infection have been helped greatly by the expression of individual proteins (and mutants) and, following their cellular localization; examples of the localization of (b) membrane protein and (c) nucleoprotein are shown. (b) Membrane protein is shown in green and nucleic acid is stained with propidium iodide (red). (c) Phase-contrast image of cells expressing a green fluorescence protein–nucleoprotein fusion protein (green). Images (a) and (b) are courtesy of Torsten Wurm, and image (c) is courtesy of Jae-Hwan You.