FIG. 1.

Screening of Arabidopsis UGTs of subfamily UGT73C for inactivation of ZON in a yeast bioassay. (A) Schematic illustration of the developed yeast bioassay. The expression of ADE2 is under the control of the engineered 3xERE-URA3 promoter (three estrogen-responsive elements in front of a minimal URA3 promoter). (B) Yeast strains transformed with the indicated members of the UGT73C gene family were spotted on SC-Leu plus 1/4-Ade plates containing the indicated amounts of ZON (ppb, or μg/liter). The strains were bioassay strain YCP908 transformed with the c-MYC-tagged UGTs of subfamily UGT73C, UGT73C1 (C1) to UGT73C6 (C6), and YCP908 transformed with an empty vector as a control (v). (C) Western blot analysis of the yeast strains used in panel B. The N-terminal c-MYC epitope tag introduced into the respective 73C UGT family members was detected. A transformant containing the empty expression vector was used as a control.