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A role for MGA2, but not SPT23, in activation of transcription of ERG1 in Saccharomyces cerevisiae
Author(s) -
Rice Caitlin,
Stukey Joseph,
McDonough Virginia
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.689.13
Subject(s) - squalene , saccharomyces cerevisiae , fatty acid desaturase , gene expression , transcription (linguistics) , mutant , chemistry , squalene monooxygenase , biochemistry , unsaturated fatty acid , fatty acid , transcription factor , transcriptional regulation , gene , biology , microbiology and biotechnology , biosynthesis , polyunsaturated fatty acid , linguistics , philosophy
A major role of the Saccharomyces cerevisiae MGA2 gene product is regulation of unsaturated fatty acid production, by controlling transcription and mRNA stability of OLE1 , the gene encoding the ?‐9 fatty acid desaturase. Lipid composition studies indicated that the mga2? strain contains elevated relative amounts of squalene when compared to wild‐type cells. The deletion of the MGA2 homologue, SPT23 , does not similarly impact squalene amounts. To explore the role of MGA2 in the regulation of sterol synthesis, ERG1 transcription was studied using an ERG1 promoter‐ lacZ reporter gene construct. We report here that in addition to Mga2p's role in regulation of unsaturated fatty acids, MGA2 is required for full basal expression of ERG1 . Mga2p was found to differentially regulate activation of ERG1 and OLE1 , as unsaturated fatty acids did not affect ERG1 expression levels as has previously been shown to control Mga2p's activation of OLE1 . The spt23? strain shows similar ERG1 expression to wild‐type cells, while the mga2?/spt23? strain shows reduced ERG1 expression, comparable to the mga2? mutant alone , suggesting that the role of regulation of ERG1 transcription is unique to Mga2p. Finally, particular exogenous unsaturated fatty acid supplementation was shown to influence cellular relative squalene amounts, which was less dependent on genotype. CR was supported by a Deans Research Award