Investigation of mechanisms underlying transcriptional regulation of Sso2536, encoding for an alcohol dehydrogenase gene (adh) in the crenarchaeon S. solfataricus has shown an active 5’ flanking region responsive to physiologically relevant DNA binding proteins. In particular, one DNA binding protein, Bald16 (Sso1352), has been identified whose levels are higher when cells are grown in the presence of the toxic benzaldehyde, substrate of the ADH enzyme; it has been proposed that this protein could act as a transcriptional activator triggering adh expression to protect cells from an environmental stress due to phenolic-derived aldehydes. Bald16 encodes for a putative transcriptional regulator, which has a bacterial homologue belonging to the Mar (Multiple Antibiotic Resistance) family of regulators involved in the control of gene expression of aromatic compound metabolism and antibiotic resistance. To better investigate the molecular mechanisms underlying transcriptional regulation in S. solfataricus, with greater attention with respect to defense response upon chemical stress, we analyzed the expression of the bald16 gene in the presence of aromatic aldehydes. Transcriptional analysis of the bald16 gene allowed the identification of a new mar-like locus in S. solfataricus composed of a putative multidrug transporter and the transcriptional regulator downstream (Sso1351, Sso1352). The genes are transcribed as a polycistronic unit whose expression is sensitive to the addition to the cell growth medium of different aromatic aldehydes. The gene encoding for the transcriptional regulator, has been expressed in E. coli and the recombinant protein purified to homogeneity. The protein is indeed a DNA binding protein, which binds site-specifically to both the adh and bald16 promoters. Western blot analysis revealed an increased Bald16 expression in cell extracts prepared from cells grown in the presence of aromatic aldehydes. These results reasonably strengthen the hypothesis of a resistance mechanism based on the coordinate expression of the adh gene and the Mar-like operon, in response to stress determined by phenolic-derived materials.

Coordinate expression of a Mar-like operon and an alcohol dehydrogenase gene contributes to detoxification by aromatic aldehydes in Sulfolobus solfataricus

FIORENTINO, GABRIELLA;RONCA, RAFFAELE;ROSSI, MOSE';BARTOLUCCI, SIMONETTA
2004

Abstract

Investigation of mechanisms underlying transcriptional regulation of Sso2536, encoding for an alcohol dehydrogenase gene (adh) in the crenarchaeon S. solfataricus has shown an active 5’ flanking region responsive to physiologically relevant DNA binding proteins. In particular, one DNA binding protein, Bald16 (Sso1352), has been identified whose levels are higher when cells are grown in the presence of the toxic benzaldehyde, substrate of the ADH enzyme; it has been proposed that this protein could act as a transcriptional activator triggering adh expression to protect cells from an environmental stress due to phenolic-derived aldehydes. Bald16 encodes for a putative transcriptional regulator, which has a bacterial homologue belonging to the Mar (Multiple Antibiotic Resistance) family of regulators involved in the control of gene expression of aromatic compound metabolism and antibiotic resistance. To better investigate the molecular mechanisms underlying transcriptional regulation in S. solfataricus, with greater attention with respect to defense response upon chemical stress, we analyzed the expression of the bald16 gene in the presence of aromatic aldehydes. Transcriptional analysis of the bald16 gene allowed the identification of a new mar-like locus in S. solfataricus composed of a putative multidrug transporter and the transcriptional regulator downstream (Sso1351, Sso1352). The genes are transcribed as a polycistronic unit whose expression is sensitive to the addition to the cell growth medium of different aromatic aldehydes. The gene encoding for the transcriptional regulator, has been expressed in E. coli and the recombinant protein purified to homogeneity. The protein is indeed a DNA binding protein, which binds site-specifically to both the adh and bald16 promoters. Western blot analysis revealed an increased Bald16 expression in cell extracts prepared from cells grown in the presence of aromatic aldehydes. These results reasonably strengthen the hypothesis of a resistance mechanism based on the coordinate expression of the adh gene and the Mar-like operon, in response to stress determined by phenolic-derived materials.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/318310
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