YMGV is a valuable tool to get an overview of the conditions in which a gene is regulated and, therefore, offers clues to its function. As an example, we queried yMGV for expression profiles concerning PDR1, whose product is a zinc finger transcription factor involved in yeast multidrug resistance. To date, no transcriptional regulation of PDR1 has been mentionned in the litterature. We observed that PDR1 is up regulated in the case of a progressive inactivation of HMG2 and ERG11 (Hughes et al., 2000 ), two genes involved in ergosterol biosynthesis.
 

The “view one gene profile” was used to query yMGV for PDR1 gene. The main varying results obtain are represented on this figure. The compendium results (Hughes et al., 2000) point out an induction of PDR1 when component of the ergosterol pathway (ERG11 and HMG2) are repressed. This graph plots the Cy3/Cy5 ratio for several conditions used in the publication.

This fits with the role of Pdr1p in the control of ergosterol synthesis pathway that has been previously demonstrated (Van den Hazel and Pichler, 1999; Kontoyannis et al., 2000). In addition, PDR1 seems to be activated by an exposure to the DNA-damaging agent Methyl Methane Sulfonate (MMS, Jelinsky et al., 2000). It would be worth testing this drug with cells in which Pdr1p activity has been altered. All these new yMGV-derived information can stimulate new pertinent approaches concerning the role of PDR1.