FIG 4.

Ribosomal protein L13a is required for SARS-CoV-2 S protein-induced suppression of translation of VAIT element-containing mRNAs. Extracts were prepared from human bronchial epithelial cells (HBTEC) (a) and human alveolar epithelial cells (A549) (b) left untreated or treated with recombinant spike protein (S1 subunit). The immunodepletion of L13a was confirmed by immunoblot (a, right panel). Extracts were added to in vitro translation reactions performed as described for Fig. 2 using the same luciferase reporter cRNAs harboring S or ORF1a VAIT elements (as shown below the panels). To test for involvement of L13a, L13a protein was immunodepleted from cell extracts by preincubation with anti-L13a antibody. IgG antibody was used as a negative control for immunodepletion.