FIG 3.

Replication-independent expression of NS1 to NS4B in HeLa cells results in dilation of the ER membrane and generation of RC-like structures. (A) Representative TEM images of control HeLa cells, cells infected with LGTV (MOI of 1), cells transfected with the TBEV DNA replicon, and uninduced and induced NSP-GFP cells. White arrowheads show dilated ER areas; black arrowheads denote replication-vesicle-like structures inside the dilated ER areas. Insets show magnifications of the indicated areas. Scale bars = 1 μm (except in insets [scale bars = 0.1 μm]). (B) Quantification of the number of dilated ER areas in replicon-transfected cells, LGTV-infected cells, and dox-induced NSP-GFP cells, compared with control HeLa cells (n = 5). Quantification was performed using ImageJ. **, P ≤ 0.05 (t test). (C) Membrane profiles and sizes of replication-vesicle-like structures in replicon-transfected cells, LGTV-infected cells, and dox-induced NSP-GFP cells. The membrane profiles were outlined using Adobe Photoshop. The diameters of at least 30 randomly chosen vesicles from each group were measured using ImageJ.