Figure 3

Isolation of antibody-reactive proteins by 2D gel electrophoresis and immunoblotting. (a) Two-dimensional gel electrophoresis of HeLa-cell nuclear extract. Molecular-weight marker positions are indicated on the left. Isoelectric focusing was in the horizontal dimension with the anode on the left. The gel is silver-stained. (b) Immunoblot from a separation similar to the one shown in (a), developed with the patient serum diluted 1:200. (c) Two-dimensional electrophoresis of a fraction of the nuclear extract purified by reversed-phase HPLC. (d) The immunoblot of the separation in (c), developed with a 1:200 dilution of patient serum. The two prominent spots marked with a circle in (c) were cut out separately and analyzed by MS after in-gel trypsin digestion.