FIGURE 5.
In vitro synthesized CF Im 68- and 25-kD subunits associate with heavy complexes, including U1 snRNP. [35-S]-methionine-labeled CF Im 68-kD and 25-kD subunits were synthesized by in vitro transcription and translation and subjected to 5%–30% sucrose density gradient centrifugation either alone (A) or after mixing with nuclear extract (B and C). In panels A and B, every other gradient fraction was immunoprecipitated using mAb 2.73. In panel C, every other fraction was precipitated with anti-U1A (mAb 1E1); note that panel C is offset from the others because it starts with fraction 2. The precipitated proteins were separated by 10% SDS-PAGE, the gels dried and autoradiographed.
