The RNA polymerase I subunit Rpa12p interacts with the stress-responsive transcription factor Msn4p to regulate lipid metabolism in budding yeast.

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
rpa12D::ayr1D 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.