FIG. 3.
Identification of amino acids essential for transactivation of snRNA and snRNA-type promoters. (A) The amino acid sequence of the Staf domain 207 to 224 is shown with the changes introduced in the mutants. Dots in the mutant sequences indicate an unchanged residue. (B) Transcriptional activation assays from the Pol II 3E.U1 and Pol III 3E.tRNASec promoters by the various effectors depicted in panel A. Activity is shown as a percentage of the activity observed with Staf-Krox-20 Δ473-600 construct containing the wild-type snRNA activation domain. Activities in microinjections assays with the 3E.U1 and 3E.tRNASec reporters are shown by solid and shaded bars, respectively. Results are the averages of two independent determinations. Identities of the effector proteins are indicated below each histogram. −, assay without effector.