The CRE1 carbon catabolite repressor of the fungus Trichoderma reesei: a master regulator of carbon assimilation
Thomas Portnoy, Antoine Margeot, Rita Linke, Lea Atanasova, Erzsébet Fekete, Erzsébet Sándor, Lukas Hartl, Levente Karaffa, Irina S Druzhinina, Bernhard Seiboth, Stéphane Le Crom, Christian P Kubicek
BMC Genomics·2011·180 citations
<jats:title>Abstract</jats:title>
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<jats:title>Background</jats:title>
<jats:p>The identification and characterization of the transcriptional regulatory networks governing the physiology and adaptation of microbial cells is a key step in understanding their behaviour. One such wide-domain regulatory circuit, essential to all cells, is carbon catabolite repression (CCR): it allows the cell to prefer some carbon sources, whose assimilation is of high nutritional value, over less profitable ones. In lower multicellular fungi, the C2H2 zinc finger CreA/CRE1 protein has been shown to act as the transcriptional repressor in this process. However, the complete list of its gene targets is not known.</jats:p>
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<jats:title>Results</jats:title>
<jats:p>Here, we deciphered the CRE1 regulatory range in the model cellulose and hemicellulose-degrading fungus <jats:italic>Trichoderma reesei</jats:italic> (anamorph of <jats:italic>Hypocrea jecorina</jats:italic>) by profiling transcription in a wild-type and a delta-<jats:italic>cre1</jats:italic> mutant strain on glucose at constant growth rates known to repress and de-repress CCR-affected genes. Analysis of genome-wide microarrays reveals 2.8% of transcripts whose expression was regulated in at least one of the four experimental conditions: 47.3% of which were repressed by CRE1, whereas 29.0% were actually induced by CRE1, and 17.2% only affected by the growth rate but CRE1 independent. Among CRE1 repressed transcripts, genes encoding unknown proteins and transport proteins were overrepresented. In addition, we found CRE1-repression of nitrogenous substances uptake, components of chromatin remodeling and the transcriptional mediator complex, as well as developmental processes.</jats:p>
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<jats:title>Conclusions</jats:title>
<jats:p>Our study provides the first global insight into the molecular physiological response of a multicellular fungus to carbon catabolite regulation and identifies several not yet known targets in a growth-controlled environment.</jats:p>
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