Transcriptional activation by DNA-bound Phx1. (A) Construction of Pap1-Phx1 chimeric protein where the N-terminal homeodomain region of Phx1 was replaced with the DNA-binding domain (DBD) of Pap1. The domain structure of full-length Phx1, N-terminally deleted one (Phx1CD; 239–942 aa), and the chimeric form (Pap1DBD-Phx1CD) that contains N-terminal region (1–117) of Pap1. (B) Freshly grown wild type (ED665) cells harboring pREP42-phx1CD (lane 1), pREP42-phx1+ (lane 2), or pREP42-pap1DBD-phx1CD (lane 3) were inoculated in liquid EMM media, and grown to OD600 of 1.0. Following cells harvest, RNA samples were analyzed by Northern blot, using gene-specific probes for ctt1+, trr1,+ or gpx1+ transcripts that encode catalase, thioredoxin reductase, or glutathione peroxidase, respectively. The ribosomal RNAs for each sample were visualized for loading control.