FUS and amyotrophic lateral sclerosis: Interestingly, 5,6-dichloro-1-β-d-ribofuranosylbenzimidazole (DRB), another RNA synthesis inhibitor, also triggered the recruitment of wild-type GFP-FUS (and the ALS-associated mutants GFP-FUSR521C and GFP-FUSP525L) to nucleoli (Figs 5D and S3), and this response was also impaired by CX5461 treatment (Fig 5D).