SIMILARITY BETWEEN NUCLEAR MATRIX PROTEINS OF VARIOUS CELLS REVEALED BY AN IMPROVED ISOLATION METHOD

Comparative analysis of nuclear matrix proteins by two-dimensional ele ctrophoresis may be greatly impaired by copurifying cytoskeletal prote ins. The present data show that the bulk of adhering cytofilaments may mechanically be removed by shearing of nuclei pretreated with vanadyl ribonucleoside complexes. Potential mechanisms of action not based on ribonuclease inhibition are discussed. To individually preserve the i ntegrity of nuclear structures, we developed protocols for the prepara tion of nuclear matrices from three categories of cells, namely leukoc ytes, cultured cells, and tissue cells. As exemplified with material f rom human lymphocytes, cultured amniotic cells, and liver tissue cells , the resulting patterns of nuclear matrix proteins appeared quite sim ilar. Approximately 300 spots were shared among the cell types. Forty- nine of these were identified, 21 comprising heterogeneous nuclear rib onucleoproteins. Heterogeneous nuclear ribonucleoproteins L and nuclea r lamin B2 isoforms were identified by amino acid sequencing and mass spectrometry. However, individually expressed proteins, such as the pr oliferating cell nuclear antigen, also pertained following application of the protocols. Thus, enhanced resolution and comparability of prot eins improve systematic analyses of nuclear matrix protein from variou s cellular sources. J. Cell. Biochem. 71:363-374, 1998. (C) 1998 Wiley -Liss, Inc.