Fenpropimorph affects uptake of uracil and cytosine in Saccharomyces cerevisiae

Abstract

Fenpropimorph was shown to inhibit the accumulation of the pyrimidine bases uracil and cytosine from the growth media in Saccharomyces cerevisiae. Uracil prototrophs of S. cerevisiae were more resistant to the growth-inhibitory effects of fenpropimorph than were uracil auxotrophs. High concentrations of uracil rescued fenpropimorph-treated uracil auxotrophs, and cytosine, which is accumulated by a separate mechanism, could also support growth of treated uracil auxotrophs. Fenpropimorph caused a significant decrease in the uptake of radiolabeled uracil, which was not due to accumulation of ergosta-8,14-dienol (ignosterol) in the treated cultures. Radiolabeled cytosine uptake was unaffected by drug treatment in a wild-type strain but was inhibited in a sterol mutant, in which ergosterol was absent from the cell. The role of fenpropimorph in causing membrane dysfunction through a mechanism other than altered sterol metabolism is discussed.

The yeast sphingolipid signaling landscape

“…Phenotypes that imply regulation of sterol metabolism by sphingolipids are discussed in this section. Several phenotypes consist of altered sensitivity to inhibitors of sterol metabolism, specifically elo2 Δ and elo3 Δ are resistant to fenpropimorph (Revardel et al, 1995; Soustre et al, 2000; Toulmay and Prinz, 2012), a fungicide which causes ignosterol accumulation inhibiting uracil uptake (Crowley et al, 1994). The elongase mutants are also resistant to SR31747 (Revardel et al, 1995; Tvrdik et al, 2000), an inhibitor of sterol isomerase activity (Silve et al, 1996).…”

The Fenpropimorph Resistance Gene FEN2 fromSaccharomyces cerevisiae Encodes a Plasma Membrane H+-Pantothenate Symporter

“…Fenpropimorph Causes an Unspecific Inhibition of Transport Proteins-Fenpropimorph inhibits the accumulation of the pyrimidine bases uracil and cytosine from growth media in S. cerevisiae (28). Uracil prototrophs of S. cerevisiae were more resistant to the growth inhibitory effects of fenpropimorph than were uracil auxotrophs.…”

SUT1 is a putative Zn[II]2Cys6‐transcription factor whose upregulation enhances both sterol uptake and synthesis in aerobically growing Saccharomyces cerevisiae cells

“…The transfer reaction was performed at 30 8C with shaking and was started by the addition of the cell suspension at a final density of D 600 20 U´mL 21 into Tris/EDTA buffer containing 100 mg´mL 21 [4][5][6][7][8][9][10][11][12][13][14] C]cholesterol at a specific activity of 10 000 d.p.m.´mg 21 and dissolved in Tergitol/ ethanol. The final concentration of Tergitol/ethanol was 4%.…”

“…Samples were applied on silica gel plates (Silica Gel 60, Merck), and the plates were developed with hexane/ diethyl ether/acetic acid (70 : 30 : 2, v/v/v). The amounts of free and esterified [4][5][6][7][8][9][10][11][12][13][14] C]cholesterol were quantified by scanning the TLC plate with an Automatic TLC-linear analyser (LB2832, Berthold).…”

“…Under these conditions, the specificity of sterol uptake toward ergosterol, the major end product of the pathway in fungi, is not tight and budding yeast cells can accommodate a wide variety of sterolic compounds [3]. However, many reports have stressed that modifications to the sterol composition in the plasma membrane can alter the activity of many integral membrane fungal transporters such as amino acid permeases [4±7], uracil and cytosine permease [8], cation transporters [9], or pumps involved in the efflux of antifungal agents [10]. These modifications were obtained as the result of mutations in the ergosterol biosynthetic pathway or with the use of sterol biosynthesis inhibitors, either of which lead to the accumulation of otherwise barely detectable intermediates.…”