PABPN1 and oculopharyngeal muscular dystrophy: To address whether the UPS mutants reduced degeneration of OPMD muscle through altering PABPN1-17ala aggregation, we analyzed PABPN1 nuclear aggregates in Act88F-PABPN1-17ala/+ thoracic muscles in the absence or presence of the UPS heterozygous mutants at day 11.