UMMS Affiliation

Program in Cell Dynamics; Department of Molecular Genetics and Microbiology

Publication Date


Document Type



Bone Neoplasms; Carrier Proteins; Cell Cycle; Cell Line, Tumor; Cell Nucleus; *Gene Expression Regulation, Neoplastic; Humans; Microscopy, Fluorescence; Mitosis; Nuclear Proteins; Osteosarcoma; Protein Binding; Protein Structure, Tertiary; Ribosomes; Tumor Suppressor Protein p53


Life Sciences | Medicine and Health Sciences


Nucleostemin (NS) is expressed in the nucleoli of adult and embryonic stem cells and in many tumors and tumor-derived cell lines. In coimmunoprecipitation experiments, nucleostemin is recovered with the tumor suppressor p53, and more recently we have demonstrated that nucleostemin exerts its role in cell cycle progression via a p53-dependent pathway. Here, we report that in human osteosarcoma cells, nucleostemin interacts with nucleophosmin, a nucleolar protein believed to possess oncogenic potential. Nucleostemin (NS) and nucleophosmin (NPM) displayed an extremely high degree of colocalization in the granular component of the nucleolus during interphase, and both proteins associated with prenucleolar bodies in late mitosis before the reformation of nucleoli. Coimmunoprecipitation experiments revealed that NS and NPM co-reside in complexes, and yeast two-hybrid experiments confirmed that they are interactive proteins, revealing the NPM-interactive region to be the 46-amino acid N-terminal domain of NS. In bimolecular fluorescence complementation studies, bright nucleolar signals were observed, indicating that these two proteins directly interact in the nucleolus in vivo. These results support the notion that cell cycle regulatory proteins congress and interact in the nucleolus, adding to the emerging concept that this nuclear domain has functions beyond ribosome production.

DOI of Published Version



Mol Biol Cell. 2008 Jul;19(7):2870-5. Epub 2008 Apr 30. Link to article on publisher's site

Journal/Book/Conference Title

Molecular biology of the cell

Related Resources

Link to Article in PubMed

PubMed ID