Cross Regulation of Phospholipid and Unsaturated Fatty Acid Biosynthesis

Abstract

Considering the requirement for unsaturated fatty acids (UFAs) to produce phospholipids, we investigated the potential cross regulation of phospholipid and UFA biosynthesis. The Δ‐9 desaturase, encoded by OLE1, is the sole source of endogenous UFAs in Saccharomyces cerevisiae. Inspection of the OLE1 promoter revealed several sequences that are close matches to the regulatory sequence, UASINO, found in many phospholipid biosynthetic genes, and is the target of regulation by Ino2p, Ino4p and Opi1p. We then examined if these proteins also play a role in regulation of OLE1 expression. Reporter gene analysis showed that when uracil prototrophy was placed under control of the OLE1 promoter, poor expression was observed in an opi1 mutant. When lacZ was placed under control of the OLE1 promoter, reporter assays confirmed that expression was poor in the opi1 mutant. Fatty acid analysis revealed that normal regulation of OLE1 occurred in response to unsaturated fatty acid (UFA) supplement in the opi1 mutant, indicating that post‐transcriptional regulation is still functional. Finally, the 2 hybrid assay was used to examine potential interactions between Opi1p and Ole1p, Ino2p, Ino4p and known OLE1 regulators Mga2p and Spt23p. While no unexpected Opi1p interactions were detected, we observed that Ino4p interacts with Mga2p in this assay. This preliminary work indicates that phospholipid regulators also play a role in regulating OLE1 expression.Support or Funding InformationWe acknowledge the support of the Hope College Biology Department, and the Hope College Dean of Natural and Applied Sciences.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.