|
Highly flexible gene expression programs are required to allow cell growth in the presence of a wide variety
of chemicals. We used genome-wide expression analyses coupled with chromatin immunoprecipitation experiments
to study the regulatory relationships between two very similar yeast transcription factors involved in the
control of multi-drug resistance phenomenon. Yrm1 (Yor172w) is a new zinc finger transcription factor, the
overproduction of which decreases the level of transcription of the target genes of Yrr1, a zinc finger
transcription factor controlling the expression of several membrane transporter encoding genes. Surprisingly,
the absence of YRR1 releases the transcriptional activity of Yrm1, which then up-regulates 23 genes, 14 of
which are also direct target genes of Yrr1. Chromatin immunoprecipitation experiments confirmed that Yrm1
binds to the promoters of the up-regulated genes only in yeast strains from which YRR1 has been deleted.
This sophisticated regulatory program can be associated with the drug resistance phenotypes of the cell.
The program-specific distribution of paired transcription factors throughout the genome may be a general
mechanism by which similar transcription factors regulate overlapping gene expression programs in response
to chemical stresses.
|