Figure 1

Immunoprecipitation using ³⁵S-methionine labeled K562 cell extract. A. 8% SDS-PAGE. ³⁵S-methionine labeled K562 cell extract was immunoprecipitated as follows: Anti-TIF1β mAb; lanes 1 to 4, anti-TIF1β positive human sera; 20% 2, 20% loading of prototype serum in lane 2; PL-12, p155/140, NHS, normal human serum; Mi-2, reference serum for each specificity. Positions of TIF1β, Su/Ago2, Ro 60, U1snRNP A (U1-A), and molecular weight markers are shown on the left. White arrowheads indicate PL-12 (lane PL-12) and p155 (TIF1γ) and p140 (TIF1α) (lane p155/140). B. 12.5% SDS-PAGE. Sequential sera from case two were tested by immunoprecipitation. Positions of components of UsnRNPs, TIF1β, and Ro-60 and molecular weight markers are shown. NHS, normal human serum; Sm, U1, anti-Sm and anti-U1RNP reference serum, respectively; TIF, transcription intermediary factor.