FIG 6.

Palmitoylation, ubiquitination, and oligomerization are important for IFITM3 restriction of HCoV entry. (A) FLIP-IN T Rex 293 cells expressing CAT or the indicated wild-type and mutant IFITM3 proteins were cultured in the presence of Tet for 24 h. Expression of the IFITM proteins was detected by Western blotting assay using anti-FLAG monoclonal antibody. β-Actin served as a loading control. (B) The above-mentioned FLP-IN T Rex-derived cells were cultured in the presence or absence of Tet for 24 h and then infected with SARSpp, NL63pp, 229Epp, MERSpp, IAVpp, or MLVpp. Luciferase activities were determined at 48 hpi. Relative infection efficiency is the ratio of the luciferase activity in cells cultured in the presence of Tet over that in cells cultured in the absence of Tet. The error bars indicate standard deviations (n = 6).