FIGURE 1.
Analysis of [35S]-methionine/cysteine-labeled nuclear proteins by sucrose gradient fractionation and immunoprecipitation using anti-U1 70K antibody, mAb 2.73. Nucleoplasmic proteins from [35S]-methionine/cysteine-labeled 293T cells were separated by centrifugation on 5%–30% sucrose density gradients. Alternate fractions were immunoprecipitated using mAb 2.73 and the immunoprecipitated proteins were separated by 12% SDS-PAGE and autoradiographed. The position of the U1 snRNP specific proteins U1 70K, U1A, and U1C and the Sm core proteins, B/B′, D1, D2, D3, E, and F are shown.
