The function of ENDOU (endonuclease, poly(U) specific, ENSG00000111405) is as follows. Endoribonuclease that cleaves single-stranded RNAs at 5' of uridylates and releases a product with a 2',3'-cyclic phosphate at the 3'-end. The UU and GU sites are more efficiently cleaved than CU and AU sites (PubMed:18936097). Targets mRNAs to regulate their expression (PubMed:37803019). {ECO:0000269|PubMed:18936097, ECO:0000269|PubMed:37803019}.