In Saccharomyces cerevisiae, RPA12 encodes the small subunit of RNA polymerase I. Here, we demonstrate that Rpa12p interacts with the transcription factor Msn4p and prevents its binding to the promoter of AYR1 encoding Ayr1p (1-acyldihydroxyacetone phosphate reductase), a key enzyme involved in triacylglycerol biosynthesis and mobilization of nonpolar lipids. Deletion of RPA12 leads to triacylglycerol accumulation due to the binding of Msn4p to the promoter of AYR1 and activation of its transcription. The double deletion rpa12Δ::ayr1Δ caused a reduction in triacylglycerol levels. Our findings reveal that Rpa12p functions as a negative regulator of lipid metabolism by modulating nonpolar lipid biosynthesis through its interaction with Msn4p.
Keywords: nonpolar lipid metabolism; transcriptional regulation; triacylglycerol.
© 2016 Federation of European Biochemical Societies.