Resolve: C9orf72 DPR blockade of nucleocytoplasmic transport

Bounty tier: $500K cellular mechanism. The challenge asks whether C9orf72 DPR species are sufficient and necessary to cause an early NUP98/RanGAP1 transport defect. Falsifiable prediction: inducible poly-GR or poly-PR expression in human iPSC motor neurons will lower NLS cargo nuclear import rate by >=35% within 48 hours, reduce NUP98 nuclear-envelope continuity by >=30%, and antisense DPR suppression will normalize >=50% of import kinetics before cell-death markers rise. The claim is weakened if transport defects appear only after caspase activation or if poly-GA alone reproduces the full effect.