Schematic representation of plasmid constructions. The tTA gene is expressed from the A. nidulans promoter in three plasmids: p473 (no selection), p434 (hygromycin resistance encoded by hph) and p444 (phleomycin resistance encoded by ble). The rtTA2S-M2 gene is expressed from the A. nidulans gpdA promoter in p474 (no selection), p502 (hygromycin selection encoded by hph) and p480 (phleomycin resistance encoded by ble). Two versions of the tetO7-hph reporter construct are shown below. Plasmid p482 contains seven copies of tetO, a 175 bp minimal gpdA promoter (Pmin), and the hph gene encoding resistance to hygromycin. Plasmid p500 contains the same components, with the addition of a 280 bp fragment of the A. fumigatus cgrA terminator region upstream of the tetO7 promoter to reduce read-through from flanking sequences. All plasmids have been deposited in the Fungal Genetics Stock Center for distribution.