The peroxisomal transporter gene ANT1 is regulated by a deviant oleate response element (ORE): characterization of the signal for fatty acid induction.
Saccharomyces cerevisiae ANT1/YPR128c encodes the peroxisomal adenine nucleotide transporter that provides ATP for intra-peroxisomal activation of medium-chain fatty acids. A lacZ reporter construct comprising the ANT1 promoter was shown to be comparatively more highly expressed in a wild-type strain grown on oleic acid, a long-chain fatty acid, than in pip2Delta(oaf1)Delta mutant cells that are defective in fatty acid induction. The ANT1 promoter was demonstrated to contain a deviant oleate response element (ORE) that could bind the Pip2p-Oaf1p transcription factor and confer activation on a basal CYC1-lacZ reporter gene. Expression of Ant1p as well as other enzymes whose genes are known to be regulated by a canonical ORE was found to be increased in cells grown on lauric acid, a medium-chain fatty acid. We concluded that the signal for induction does not differentiate between long- and medium-chain fatty acids. This signal was independent of beta-oxidation or the biogenesis of the peroxisomal compartment where this process occurs, since a pox1Delta strain blocked in the first and rate-limiting step of beta-oxidation as well as various pex mutant cells devoid of intact peroxisomes produced sufficient amounts of Pip2p-Oaf1p for binding OREs in vitro and for expressing an ORE-driven reporter gene. The signal's durability was shown to be related to the concentration of fatty acids in the medium, since a pex6Delta strain expressed an ORE-driven reporter gene at high levels for a longer period than did isogenic wild-type cells. Generation of the signal was also independent of protein synthesis, as demonstrated by cycloheximide treatment.
Rottensteiner
Hanspeter
H
FU Berlin, FB Biologie, Chemie, Pharmazie, Thielallee 63, D-14195 Berlin, Germany.
Palmieri
Luigi
L
Hartig
Andreas
A
Hamilton
Barbara
B
Ruis
Helmut
H
Erdmann
Ralf
R
Gurvitz
Aner
A
D000255:Adenosine Triphosphate / Q000378:metabolism; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism*; D003513:Cycloheximide / Q000494:pharmacology; D005227:Fatty Acids / Q000737:chemistry / Q000494:pharmacology*; D005800:Genes, Fungal / Q000187:drug effects; D017930:Genes, Reporter; D007763:Lac Operon; D033704:Nucleotide Transport Proteins; D019301:Oleic Acid / Q000494:pharmacology; D020675:Peroxisomes / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction
C430871:ANT1 protein, S cerevisiae; D002352:Carrier Proteins; D005227:Fatty Acids; D033704:Nucleotide Transport Proteins; D011500:Protein Synthesis Inhibitors; D029701:Saccharomyces cerevisiae Proteins; D019301:Oleic Acid; D000255:Adenosine Triphosphate; D003513:Cycloheximide