Genome-wide screen implicates lipid metabolism in transcriptional regulation of Protein Kinase A subunits

PAUTASSO C, CAÑONERO L, CHUA G, ZAREMBERG V, ROSSI S.

Halifax, NS, Canada

Conferencia; 11th Yeast Lipid Conference; 2013

Transcriptional regulation is a key mechanism controlling the response of cells to diverse stimuli. The identification of regulators mediating 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 PKA subunits promoters. Positive and negative transcription regulators were classified into functionally related groups based on Gene Ontology. This analysis revealed an enrichment in genes with roles in lipid and phosphate metabolisms, cytoskeleton organization and transcription regulation. Results of the genetic screen were validated by using β-galactosidase reporter assay and qRT-PCR. We report the results obtained from different strains lacking genes involved in PA-mediated regulation of phospholipid synthesis. TPK1 and TPK2 promoters activities were increased in ino2Δ, ino4Δ and dgk1Δ strains, while decreased in opi1Δ cells. BCY1 promoter showed the opposite behavior. TPK1, TPK2 and BCY1 promoters activities responded to the presence of inositol in the culture medium. TPK3 promoter showed no change, neither in inositol supplemented culture nor in the different deletion strains. These results implicate glycerolipid metabolism in the differential regulation of PKA subunits transcription