Quantification of Ag-NOR proteins using Ag-NOR staining on western blotsP Roussel, V Sirri and D Hernandez-Verdun Institut Jacques Monod, Paris, France. Ribosomal genes are associated with a set of silver-stained nucleolar proteins, the Ag-NOR proteins, whose amount is directly related to the duration of the cell cycle. Quantification of Ag-NOR proteins by image analysis is presently used to evaluate the rate of proliferation of cancer cells and nucleolar activity. Our objective was to establish a procedure to quantify independently each major Ag-NOR protein in cell extracts. Computerized densitometry established that the specific silver staining of Ag-NOR proteins (Ag-NOR staining) performed on Western blots makes it possible to quantify Ag-NOR proteins. Using purified Ag-NOR proteins, nucleolin, and protein B23, we observed that the intensity of Ag-NOR staining is proportional to the amount of protein. A linear relationship exists between the intensity of Ag-NOR staining and the amount of nucleolin, in the range of 0.2-1.6 micrograms. Using total nuclear extracts prepared from mammalian cells, the proportionality was maintained for total Ag-NOR-stained proteins or for a particular protein. We also determined the levels of nuclear proteins suitable for quantitative analysis. Individual Ag-NOR proteins can be quantified by computerized densitometry in nuclear extracts after Ag-NOR staining on Western blots. This procedure can be applied to establish the contribution of each Ag-NOR protein in general staining, estimate the variability of each Ag-NOR protein in normal and pathological conditions, and quantify each Ag-NOR protein contained per cell.
Volume 42,
Issue 11,
pp. 1513-1517,
11/01/1994
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A. TorresMontaner, J. Bolívar, A. Astola, J. A. GimenezMas, J. A. Brieva, and M. M. Valdivia Immunohistochemical Detection of Ribosomal Transcription Factor UBF and AgNOR Staining Identify Apoptotic Events in Neoplastic Cells of Hodgkin's Disease and in Other Lymphoid Cells J. Histochem. Cytochem., November 1, 2000; 48(11): 1521 - 1530. [Abstract] [Full Text] |
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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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