Genome-Wide Screen implicates lipid metabolism in transcriptional regulation of protein kinase A subunits

PAUTASSO, CONSTANZA; CAÑONERO, LUCIANA; CHUA, GORDON; ZAREMBERG, VANINA; ROSSI, SILVIA

Halifax

Congreso; 11th Yeast Lipid Conference; 2013

Yeast Lipid Conference

Transcriptional regulation is a key mechanism that controls the fate and response of cells to diverse signals. Therefore the identification of regulators which mediate these signals is a crucial step to elucidate how cell fate is regulated. In Saccharomyces cerevisiae, three genes encode the PKA catalytic subunit, TPK1, TPK2, TPK3, while the regulatory subunit is encoded by only one gene, BCY1. We have used a dual reporter gene system to survey the yeast deletion collection in order to identify regulators of TPK1, TPK2, TPK3 and BCY1 promoters. Positive and negative transcription regulators were identified and classified into functionally related groups based on Gene Ontology. This analysis revealed an enrichment in genes with roles in lipid and phosphate metabolism, cytoskeleton organization and transcription regulation. Results of the genetic screen were further validated by using β-galactosidase reporter assay and qRT-PCR. We report the results obtained from different strains lacking genes involved in phosphatidic acid (PA)-mediated regulation of phospholipid synthesis. The activities of TPK1 and TPK2 promoters were increased in ino2Δ, ino4Δ and dgk1Δ strains, while decreased in opi1Δ cells. The opposite behavior was observed for the activity of the BCY1 promoter. Furthermore, the activity of TPK1, TPK2 and BCY1 promoters responded to the presence of inositol in the culture medium. TPK3 promoter showed no change in its activity, neither in inositol supplemented cultures nor in the different deletion strains assessed. These results implicate glycerolipid metabolism in the differential regulation of PKA subunits transcription.