Stem Cells

Nucleolar Proteins and Self-Renewal

Science's STKE  10 Dec 2002:
Vol. 2002, Issue 162, pp. tw460-TW460
DOI: 10.1126/stke.2002.162.tw460

There is great interest in elucidating how stem cells regulate their proliferative state, endowing them with the property of self-renewal. Tsai and McKay report that nucleolar proteins may contribute to this phenomenon. Their study has identified a nucleolar protein called nucleostamin that is expressed in central nervous system stem cells, embryonic stem cells, and several cancer cell lines. Its expression decreased when stem cells differentiated, suggesting that it functions to maintain cell proliferation. However, overexpression of nucleostamin prevented cells from entering mitosis and increased cell death. This effect was dependent on the expression of p53, a tumor suppressor protein that also coimmunoprecipitated with nucleostamin from cell extracts. Nucleostamin also harbors a guanosine triphosphate-binding domain that the authors propose regulates nucleolar localization.

R. Y. L. Tsai, R. D. G. McKay, A nucleolar mechanism controlling cell proliferation in stem cells and cancer cells. Genes Dev. 16, 2991-3003 (2002). [Abstract] [Full Text]