Amount variability of total and individual Ag-NOR proteins in cells stimulated to proliferateV Sirri, P Roussel, D Trere, M Derenzini and D Hernandez-Verdun Institut Jacques Monod, Paris, France. Ribosomal genes are associated with a subset of acidic proteins called Ag-NOR proteins. The amount of nucleolar Ag-NOR proteins varies, depending on nucleolar activity and/or cell proliferation. To understand the linkage between the amount of Ag-NOR proteins, ribosome biogenesis, and cell proliferation, we investigated the variability of Ag-NOR proteins in rRNA-stimulated cells maintained in G1 and in rRNA- stimulated cells entering the mitotic cycle. Rat hepatocytes were stimulated with cortisol for rRNA synthesis (1, 4, and 8 hr) and the cell cycle was induced by hepatectomy in regenerating hepatocytes (3-21 hr). In non-stimulated hepatocytes, nucleolin and protein B23 were the two major Ag-NOR proteins, corresponding to 70% of total Ag-NOR staining. In hepatocytes stimulated for rRNA synthesis in G1, the amount of Ag-NOR proteins was only slightly increased, whereas in cycle- stimulated cells it was increased 3.04-fold. This is the consequence of a differential increase of the major Ag-NOR proteins that appears earlier and is proportionally more important for nucleolin (3.5-fold) than for protein B23 (twofold) and also for the increase of several minor Ag-NOR proteins. We conclude that, in dividing cells, the mean value of the Ag-NOR proteins measured reflects the percentage of cells in the different phases. This could explain why the amount of Ag-NOR proteins can be used as a marker of cell proliferation.
Volume 43,
Issue 9,
pp. 887-893,
09/01/1995
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Y.-L. Wu, C. Dudognon, E. Nguyen, J. Hillion, F. Pendino, I. Tarkanyi, J. Aradi, M. Lanotte, J.-H. Tong, G.-Q. Chen, et al. Immunodetection of human telomerase reverse-transcriptase (hTERT) re-appraised: nucleolin and telomerase cross paths J. Cell Sci., July 1, 2006; 119(13): 2797 - 2806. [Abstract] [Full Text] [PDF] |
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K. Weipoltshammer, C. Schofer, M. Almeder, V. V. Philimonenko, K. Frei, F. Wachtler, and P. Hozak Intranuclear Anchoring of Repetitive DNA Sequences: Centromeres, Telomeres, and Ribosomal DNA J. Cell Biol., December 27, 1999; 147(7): 1409 - 1418. [Abstract] [Full Text] [PDF] |
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M. Srivastava and H. B. Pollard Molecular dissection of nucleolin's role in growth and cell proliferation: new insights FASEB J, November 1, 1999; 13(14): 1911 - 1922. [Abstract] [Full Text] |
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H Ginisty, H Sicard, B Roger, and P Bouvet Structure and functions of nucleolin J. Cell Sci., January 3, 1999; 112(6): 761 - 772. [Abstract] [PDF] |
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