C9orf72 Poly(PR) Dipeptide Repeats Disturb Biomolecular Phase Separation and Disrupt Nucleolar Function

？ R-rich DPRs sequester NPM1 into large, soluble phase-separation-inhibited complexes ？ NPM1 sequestration dissolves droplets in vitro and delocalizes nucleolar NPM1 in cells ？ poly(PR) entraps rRNA in static puncta in vitro and in nucleoli ？ poly(PR) interactions disrupt nucleolar organization in a length-dependent manne