Global Regulatory Functions of Oaf1p and Pip2p (Oaf2p), Transcription Factors That Regulate Genes Encoding Peroxisomal Proteins in Saccharomyces cerevisiae

ABSTRACT

Two transcription factors, Oaf1p and Pip2p (Oaf2p), are key components in the pathway by which several Saccharomyces cerevisiae genes encoding peroxisomal proteins are activated in the presence of a fatty acid such as oleate. By searching the S. cerevisiae genomic database for the consensus sequence that acts as a target for these transcription factors, we identified 40 genes that contain a putative Oaf1p-Pip2p binding site in their promoter region. Quantitative Northern analysis confirmed that the expression of 22 of the genes identified is induced by oleate and that either one or both of these transcription factors are required for the activation. In addition to known peroxisomal proteins, the regulated genes encode novel peroxisomal proteins, a mitochondrial protein, and proteins of unknown location and function. We demonstrate that Oaf1p regulates certain genes in the absence of Pip2p and that both of these transcription factors play a role in maintaining the glucose-repressed state of one gene. Furthermore, we provide evidence that the defined consensus binding site is not required for the regulation of certain oleate-responsive genes.

ACKNOWLEDGMENTS

We acknowledge and thank Murl Casey for excellent technical assistance. We also extend thanks to the yeast curator at Stanford University for assistance with the yeast genome database search and to Joel Lopez for assistance with the Northern analysis of YOL002c.

This research was supported by American Heart Association grants 95008910 and 92001690 and by NIH grant R55DKOD51992.