NPM1 and amyotrophic lateral sclerosis: PolyGR- and polyPR-associated loss in nucleolar integrity has been demonstrated in cell lines derived from C9-ALS patients by imaging the migration and localization of nucleolar proteins, including nucleolin and nucleophosmin, which are crucial for chromatin remodeling (Haeusler et al., 2014; Kwon et al., 2014).