FIG. 2.
A 50-aa region of SNAP190 is required for cooperative binding of the complex with TBP. (A) EMSA performed with the proteins indicated above the lanes and a probe containing the wild-type mouse U6 PSE and either the wild-type or a mutated human U6 TATA box as indicated above the lanes. In panels A to C, the upper complex in the doublet observed with stmSNAPc#1 (#1) is labeled with an asterisk to the left of the complex, and the upper complex of the doublet observed with stmSNAPc#1 and TBP is labeled with an arrowhead to the left of the complex. α-190, anti-SNAP190 antibody; −, only complex #1 was added. (B) EMSA performed with the proteins indicated above the lanes and a probe containing the wild-type mouse U6 PSE and the human U6 TATA box. The absence (−) or presence of the stmSNAPc proteins (indicated by the stmSNAPc number) is indicated over the lanes. The absence (−) and amount (indicated by the height of the triangle) of TBP is indicated over the gel. TBP was titrated over a threefold range. The protein-DNA complexes containing the stmSNAPcs only or both the stmSNAPcs and TBP are indicated. (C) EMSA performed with the proteins indicated above the lanes and a probe containing a wild-type mouse U6 PSE and a mutated TATA box. The presence or absence (−) and the amount (indicated by the height of the triangle over the lanes) of TBP are indicated over the lanes.