Background And Aims: biological processes in all organisms are controlled by environmental conditions, however, information concerning the molecular responses to external pH is scarce. In this work we studied the pH response of UGA4 gene encoding delta-aminolevulinic acid and gamma-aminobutyric acid permease in Saccharomyces cerevisiae.
Methods: we analyzed the effect of pH on the expression of UGA4 gene measuring beta-galactosidase activity in cells carrying a UGA4::lacZ fusion gene.
Results: results indicate that UGA4 expression is higher at acidic pH. The expression of UGA3 and UGA35 genes, which encode two positive transcription factors, is not regulated by external pH, while the expression of UGA43 gene encoding a repressor of UGA4 transcription is dependent on pH. Using a strain lacking Uga43p we clearly showed that the effect of ambient pH on UGA4 expression is not a secondary effect of the pH regulation on UGA43. We have also demonstrated that the effect of pH can only be detected when UGA4 gene is not subject to a strong repression by Uga43p nor to GABA induction.
Conclusion: here, we demonstrate that UGA4 is an acid-expressed gene. This regulation is probably mediated by Rim101p through the consensus site 5'-GCCARG-3' at 237 bp preceding the UGA4 coding sequence (201).
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http://dx.doi.org/10.1016/s1357-2725(01)00085-1 | DOI Listing |
J Gen Appl Microbiol
May 2018
The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University.
γ-aminobutyric acid (GABA) is an important non-protein amino acid involved in the response to various environmental stresses in plant cells. The objectives of this study was to test the hypothesis that intracellular accumulation of GABA improves osmotic tolerance in the unconventional yeast Candida glycerinogenes. In C.
View Article and Find Full Text PDFMicrobiology (Reading)
November 2017
Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN). Buenos Aires, Argentina.
Yeast cells can use γ-aminobutyric acid (GABA), a non-protein amino acid, as a nitrogen source that is mainly imported by the permease Uga4 and catabolized by the enzymes GABA transaminase and succinate-semialdehyde dehydrogenase, encoded by the UGA1 and UGA2 genes, respectively. The three UGA genes are inducible by GABA and subject to nitrogen catabolite repression. Hence, their regulation occurs through two mechanisms, one dependent on the inducer and the other on nitrogen source quality.
View Article and Find Full Text PDFJ Amino Acids
October 2015
Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Ciudad Universitaria, 1428 Buenos Aires, Argentina.
Yeast can use a wide variety of nitrogen compounds. However, the ability to synthesize enzymes and permeases for catabolism of poor nitrogen sources is limited in the presence of a rich one. This general mechanism of transcriptional control is called nitrogen catabolite repression.
View Article and Find Full Text PDFAppl Microbiol Biotechnol
March 2015
School of Chemical and Biological Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-744, Republic of Korea.
A wide range of promoters with different strengths and regulatory mechanisms are valuable tools in metabolic engineering and synthetic biology. While there are many constitutive promoters available, the number of inducible promoters is still limited for pathway engineering in Saccharomyces cerevisiae. Here, we constructed aromatic amino-acid-inducible promoters based on the binding sites of Aro80 transcription factor, which is involved in the catabolism of aromatic amino acids through transcriptional activation of ARO9 and ARO10 genes in response to aromatic amino acids.
View Article and Find Full Text PDFMicrob Cell Fact
December 2013
S,F,M,B,, Université Libre de Bruxelles, Blvd, du Triomphe, Bâtiment BC, local 1C4,208, B-1050 Bruxelles, Belgium.
Background: Decades of work requiring heterologous expression of eukaryotic proteins have shown that no expression system can be considered as the panacea and the appropriate expression strategy is often protein-dependent. In a large number of cases, yeasts have proven to be reliable organisms for heterologous protein expression by combining eukaryotic cellular organization with the ease of use of simpler microorganisms.
Results: During this work, a novel promoter system based on the nitrogen catabolite regulation has been developed to produce the general amino acid permease (Gap1) in its natural host, the yeast Saccharomyces cerevisiae.
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