RSU1 and fibrosarcoma: To facilitate the studies on RSU1, we knocked out RSU1 from human HT1080 fibrosarcoma cells (hereinafter referred to as RSU1 KO cells) using the CRISPR/Cas9 techniques with the gRNA directing to exon 1 of RSU1. DNA sequencing revealed insertion mutations at RSU1 loci (Fig. 1B), and the disruption of RSU1 was further confirmed by Western blotting with anti-RSU1 antibody (Fig. 1A).