Fig. 2: Expression of LDLR increases virus infection by promoting cell entry.

a Relative vRNA levels in WT HEK 293T cells and cells stably overexpressing hamster LDLR. For binding, cells were harvested 30 min after incubation with GETV-HN at 4 °C. For internalization, unbound viruses were removed and cells were incubated further at 37 °C for 1 h before harvest. vRNA levels were measured by qRT-PCR; data was normalized relative to WT cells. Data are presented as mean values ± SD (n = 4 independent experiments) and two-tailed P-values are calculated by unpaired Student’s t test. b Orthogonal (left) and 3D (center, right) views of receptor and virus colocalization by confocal fluorescence imaging. Cells were transfected with LDLR-Flag or LDLRAD3-Flag plasmid and incubated with rGETV-mCherry virions before immunostaining with anti-Flag M2 antibody. Scale bar, 10 μm. The 3D image shows two different angles, from top to down (center) and from front to back (right). Data are presented as means ± SD (n  =  75 cells examined over three independent experiments). c, d Flow cytometry analysis of WT, ΔMxra8, ΔLdlr or Δ Mxra8+ΔLdlr BHK-21 cell lines infected with rGETV-EGFP (MOI = 0.001). Viral titers in supernatants were measured by titration on BHK-21 cells. e, f Flow cytometry analysis of ΔLdlr, Δ Mxra8+ΔLdlr or ΔMxra8 BHK-21 cells transfected with LDLR expression plasmid or mock-transfected prior rGETV-EGFP infection (MOI = 0.001). g qRT-PCR analysis of infection efficiency of Seneca Valley virus (SVV) and Pseudorabies virus (PRV) at MOI of 0.1 in WT, ΔMxra8, ΔLdlr, and Δ Mxra8+ΔLdlr BHK-21 cells. Results are normalized to WT BHK-21 cells in (c–g). h-k Flow cytometry analysis of rGETV-EGFP (MOI = 0.1) infection in WT and ΔLDLR ST and LLC-PK1 cell lines. Results are normalized relative to WT cells. For flow cytometry, data are presented as mean values ± SD (n = 3 independent experiments) and two-tailed P-values are calculated by unpaired Student’s t test (c–k). Unless otherwise labeled, the displayed P-values are the significance between the experimental group and the control group (WT, Control or LDLRAD3-Flag). Source data are provided as a Source Data file.