Figure 2.
Subcellular localization of SARS-CoV-2 RNA and proteins in infected human placenta PCSs
(A) Representative in situ hybridization micrographs of the RNA of SARS-CoV-2 S protein (pink) in cross-sections of placenta PCSs infected with 5 × 105 PFU of SARS-CoV-2. The green arrows indicate S protein RNA+ cells compatible with Hofbauer cell morphology. The sections were counterstained with hematoxylin. Scale bar, 200 μm.
(B) Representative illustrations of mock- and SARS-CoV-2 infected placenta PCSs analyzed 72 and 120 h p.i. DAPI (blue) SARS-CoV-2 N protein (green) and CANX (red). Scale bar, 10 μm.
(C) High-resolution 3-dimensional (3D) stacks. Upper panels: bright-field images showing the microstructure of human placenta villi. The colored squares represent the zoomed area depicted in the lower panels, which are representative illustrations of syncytiotrophoblasts, expressing CANX (red) and SARS-CoV-2 N protein (green). In the lower panel, the white signal indicates SARS-CoV-2 N protein and CANX co-localization. The percentages of SARS-CoV-2 N protein signal co-localizing with CANX signal are indicated (coloc.). Blue scale bar, 10 μm; white scale bar, 2 μm.
(D) Representative illustrations of mock- and SARS-CoV-2-infected placenta PCSs analyzed 24, 72, and 120 h p.i. DAPI (blue) SARS-CoV-2 N protein (green) and ERp57 (red). Scale bar, 5 μm.
(E) Representative illustrations of mock- and SARS-CoV-2-infected placenta PCSs analyzed 24, 72, and 120 h p.i. DAPI (blue) SARS-CoV-2 S protein (green) and ERp57 (red). Scale bar, 20 μm.