Extended Data Fig. 8: Impact of ST6GAL1 siRNA knockdown on sialic acid abundance.
From: Genetic risk factors for COVID-19 and influenza are largely distinct
a, Flow cytometry histograms (geometric mean across three replicates) of siRNA-transfected cells stained with FITC-conjugated S. Nigra (SNA) Lectin 72 hours post-transfection to measure membrane-level sialic acid. A small proportion of cells treated with ST6GAL1 siRNAs displayed high fluorescence levels, consistent with incomplete transfection. b, Bar graph showing mean fluorescence intensity at the maximum from histogram in a. Bars represent the average across replicates from three experiments, points represent values from the individual replicates, and lines show the width of the distribution of individual experiments. In comparison to the negative control, membrane-level sialic acid dropped by 79–92% after ST6GAL1 knockdown. c,d, Representative images of ST6GAL1 and GAPDH protein levels measured in A549 cells 72 hours after treatment with siRNAs at concentration 5 to 40 μM (c) and at the final selected concentration of 10 μM (d). e, Quantification of ST6GAL1 and GAPDH protein levels in A549 cells treated with 10 μM of ST6GAL1 siRNA, based on three individual replicates. Protein levels are normalized to beta-actin and shown relative to the negative control siRNA. Uncropped gels are provided as Source Data. P-values derived from a two-sided Wilcoxon Rank Sum Test and asterisks (*) mark those experiments with P < 0.05.
