Fig. 2.

Validation of yCCR4 as a gene needed for TR action in yeast. (A) Comparison of hTRβ1 activation in WT and CCR4 deletion strains. Results of β-gal assays performed with commercial (ATCC) WT yeast strain YBR175W BY4741 (4741-WT) and CCR4 deletion mutant yeast strain YAL021C BY4741 (4741-ΔyCCR4). This strain was transformed with a single copy of the chicken lysozyme (F2) TRE, hTRβ₁, GRIP1, or empty vector. Cultures were treated with vehicle (empty bars) or 10⁻⁷ M Triac (solid bars). β-Gal activities were expressed as Miller units per milligram protein. Data shown were pooled from 3 independent experiments and calculated as mean ± SE. β-Gal assays were performed as described as outlined in Materials and Methods. (B) CCR4 replacement restores TH-dependent gene activation in the CCR4 deletion strain. Experimental procedures and β-gal assays were performed as described in A except that the LexA plasmid was substituted for GRIP1/SRC2 with the same selection marker restrictions.