Nucleolin (NCL), a eukaryotic nucleolar phosphoprotein, is involved in the synthesis and maturation of ribosomes. The intron 11 of the NCL gene encodes a small nucleolar RNA, termed U20. During interphase, the protein has a distinct punctate nucleolar localization. UBF is a nucleolar phosphoprotein with both DNA binding and transactivation domains. U protein and the small nucleolar RNA binding protein. This gene encodes a nucleolar protein with an LIS1 homology domain. The heterochromatic regions are the areas near the centromeres and nucleolar organizers. Coilin has been shown to interact with ataxin 1, nucleolar phosphoprotein p130, SMN, and SNRPB. This gene is a member of the H/ACA snoRNPs (small nucleolar ribonucleoproteins) gene family. This nucleolar stress eventually causes decreased cell proliferation and death. Other proteins that make up the CB include snRNPs and nucleolar snoRNPs. In human endometrial cells, a network of nucleolar channels is sometimes formed. These regions are called nucleolar organizer regions (NOR). Because of their close association with nucleoli, he named them "nucleolar accessory bodies".