This entry represents the C-terminal domain of the U3 small nucleolar RNA-associated protein 15 (UTP15). This protein is involved in nucleolar processing of pre-18S ribosomal RNA, and is required for optimal pre-ribosomal RNA transcription by RNA polymerase I together with a subset of U3 proteins required for transcription (t-UTPs). UTP15 is a component of the ribosomal small subunit (SSU) processome, which is a large ribonucleoprotein (RNP) required for processing of precursors to the small subunit RNA, the 18S, of the ribosome [, ]. This domain is found C-terminal to the WD40 repeat (). UTP15 associates with U3 snoRNA, which is ubiquitous in eukaryotes and is required for nucleolar processing of pre-18S ribosomal RNA [].