Fig. 1. Physical interaction between STAT6-TAD and p100. (A and B) STAT6-TAD interacts specifically with several nuclear proteins. Aliquots of nuclear lysates from [³⁵S]methionine-labeled or unlabeled Ramos B lymphocytes were incubated with either GST alone or with GST–St6TAD. The bound proteins were subjected to SDS–PAGE and visualized by autoradiography (A) or silver staining (B). The band corresponding to the 100 kDa protein was cut out from silver-stained gel and subjected to trypsin digestion and MALDI-TOF mass spectrometry. The lower panel in (B) is the loading control of GST–St6TAD and GST proteins.