3'-5'-exoribonuclease that specifically recognizes RNAs polyuridylated at their 3' end and mediates their degradation. Component of an exosome-independent RNA degradation pathway that mediates degradation of cytoplasmic mRNAs that have been deadenylated and subsequently uridylated at their 3'. Cleaved by caspase ced-3 in vitro. RNAi-mediated knockdown in a ced-3 and ain-1 double mutant background reduces the percentage of animals with developmental defects including production of ectopic seam cells. Belongs to the RNR ribonuclease family. DIS3L2 subfamily.