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Regulation of cardiolipin synthase levels in Saccharomyces cerevisiae
Author(s) -
Su Xuefeng,
Dowhan William
Publication year - 2006
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.1352
Subject(s) - cardiolipin , biology , derepression , saccharomyces cerevisiae , biochemistry , phosphatidylglycerol , gene expression , inositol , lac operon , microbiology and biotechnology , gene , phospholipid , phosphatidylcholine , receptor , psychological repression , membrane
The Saccharomyces cerevisiae cardiolipin (CL) synthase encoded by the CRD1 gene catalyses the synthesis of CL, which is localized to the inner mitochondrial membrane and plays an important role in mitochondrial function. To investigate how CRD1 expression is regulated, a lacZ reporter gene was placed under control of the CRD1 promoter and the 5′‐untranslated region of its mRNA (P CRD 1 ‐ lacZ ). P CRD 1 ‐ lacZ expression was 2.5 times higher in early stationary phase than in logarithmic phase for glucose grown cells. Non‐fermentable growth resulted in a two‐fold elevation in expression relative to glucose grown cells. A shift from glycerol to glucose rapidly repressed expression, whereas a shift from glucose to glycerol had the opposite effect. The derepression of P CRD 1 ‐ lacZ expression by non‐fermentable carbon sources was dependent on mitochondrial respiration. These results support a tight coordination between translation and transcription of the CRD1 gene, since similar effects by the above factors on CRD1 mRNA levels have been reported. In glucose‐grown cells, P CRD 1 ‐ lacZ expression was repressed 70% in a pgs1 Δ strain (lacks phosphatidylglycerol and CL) compared with wild‐type and rho − cells and elevated 2.5‐fold in crd1 Δ cells, which have increased phosphatidylglycerol levels, suggesting a role for phosphatidylglycerol in regulating CRD1 expression. Addition of inositol to the growth medium had no effect on expression. However, expression was elevated in an ino4 Δ mutant but not in ino2 Δ cells, suggesting multiple and separate functions for the inositol‐responsive INO2 / INO4 gene products, which normally function as a dimer in regulating gene function. Copyright © 2006 John Wiley & Sons, Ltd.