Functional analysis of the promoter of the yeast SNQ2 gene encoding a multidrug resistance transporter that confers the resistance to 4-nitroquinoline N-oxide

The yeast gene SNQ2, which encodes a multidrug resistance ABC superfamily protein, is required for resistance to the mutagen 4-nitroquinoline N-oxide (4-NQO). The expression of the SNQ2 gene is under the control of a regulatory network that involves the transcription factor Yrr1p, as well as Pdr1p/Pdr3p (Cui et al., Mel. Microbiol., 29, 1307-1315 (1998)). By 5'-deletion analysis of the promoter by using SNQ2-lacZ fusion constructs, four regions: -745 to -639 (region I), -639 to -578 (region II), -548 to -533 (region III) and -533 to -485 (region IV) were found to be important for SNQ2 expression. Genetic analysis suggested that the site in region IV was responsible for the Yrr1p-mediated SNQ2 expression. A consensus motif known for the binding of Pdr1p/Pdr3p (PDRE) was not found in region IV.