Fig. 1: csRNA and RBP clusters are dependent on HS biogenesis.

a, Representative images of U2OS cells co-stained with Siglec-11 (yellow) and 9D5 (magenta). An enlargement of the hatched box is shown, and a bright field (BF) is shown to represent the outline of the cell membrane. The nearest neighbour distance analysis of the Siglec pairs is also imaged (bottom). For each pair, the distance (µm) from that anchor (left side protein name in the figure key) to the other pair was calculated across the indicated number of cells. These values were plotted in a density histogram. b, Dot plot of genes identified in the genome-wide CRISPR-KO screen for the loss of Siglec-11 cell surface binding ranked by CRISPR score. The top 15 gene names are displayed, with cut-off shown. The inset illustrates how Siglec-11 could interact with a glycoRNA. c, Dot plot of genes identified in the genome-wide KO screen as in panel b, for the loss of 9D5 cell surface binding. The inset illustrates how 9D5 could interact with a glycoRNA. d, Upset plot analysis of genes with a score cut-off of −0.8 from the Siglec-11, 9D5 and MAA-I genome-wide KO screens. The common overlapping hits between 9D5 and Siglec-11 are highlighted in blue. The total number of hits for each intersection is noted. Statistical assessment was performed with a hypergeometric test and P values are shown without adjustment. e, Representative images of WT and KO U2OS cells stained live with 10E4, Siglec-11–Fc, 9D5 and Siglec-7 (all in red). Ab, antibody; dsRNA, double-stranded RNA; mE, mEmerald. f, Quantification of the indicated signal dot numbers and intensity per cell from panels e,g from three independent experiments. Mut, mutant. g, Representative images of the indicated cell lines stained live with anti-DDX21 and anti-hnRNP-U (both in red).