Search results for "repression"

Structure-based analyses of Salmonella RcsB variants unravel new features of the Rcs regulon

2021

18 páginas, 7 figuras, 2 tablas

Cloning and characterization of PRB1, a Candida albicans gene encoding a putative novel endoprotease B and factors affecting its expression

2002

Abstract Several cDNA fragments corresponding to transcripts differentially expressed under conditions that favor mycelial growth of Candida albicans were identified by the “differential display” technique. One of these was cloned and used as a probe to rescue the full gene from a genomic library of the fungus. The sequence identified a single, uninterrupted open reading frame of 1395 nucleotides encoding a putative protein of 465 residues and a theoretical molecular weight of 50.3 kDa, present in the genome as a single copy located at chromosome 2 in different strains. The gene product showed high homology with subtilisin-like proteases, mainly PRB1, the vacuolar B protease from Saccharomy…

Regulation of tartrate metabolism by TtdR and relation to the DcuS–DcuR-regulated C4-dicarboxylate metabolism of Escherichia coli

2009

Escherichia coli catabolizes l-tartrate under anaerobic conditions to oxaloacetate by the use of l-tartrate/succinate antiporter TtdT and l-tartrate dehydratase TtdAB. Subsequently, l-malate is channelled into fumarate respiration and degraded to succinate by the use of fumarase FumB and fumarate reductase FrdABCD. The genes encoding the latter pathway (dcuB, fumB and frdABCD) are transcriptionally activated by the DcuS–DcuR two-component system. Expression of the l-tartrate-specific ttdABT operon encoding TtdAB and TtdT was stimulated by the LysR-type gene regulator TtdR in the presence of l- and meso-tartrate, and repressed by O2 and nitrate. Anaerobic expression required a functional fn…

Symmetry Breaking and Establishment of Dorsal/Ventral Polarity in the Early Sea Urchin Embryo

2015

The mechanisms imposing the Dorsal/Ventral (DV) polarity of the early sea urchin embryo consist of a combination of inherited maternal information and inductive interactions among blastomeres. Old and recent studies suggest that a key molecular landmark of DV polarization is the expression of nodal on the future ventral side, in apparent contrast with other metazoan embryos, where nodal is expressed dorsally. A subtle maternally-inherited redox anisotropy, plus some maternal factors such as SoxB1, Univin, and p38-MAPK have been identified as inputs driving the spatially asymmetric transcription of nodal. However, all the mentioned factors are broadly distributed in the embryo as early as no…

Functioning of DcuC as the C 4 -Dicarboxylate Carrier during Glucose Fermentation by Escherichia coli

1999

ABSTRACT The dcuC gene of Escherichia coli encodes an alternative C 4 -dicarboxylate carrier (DcuC) with low transport activity. The expression of dcuC was investigated. dcuC was expressed only under anaerobic conditions; nitrate and fumarate caused slight repression and stimulation of expression, respectively. Anaerobic induction depended mainly on the transcriptional regulator FNR. Fumarate stimulation was independent of the fumarate response regulator DcuR. The expression of dcuC was not significantly inhibited by glucose, assigning a role to DcuC during glucose fermentation. The inactivation of dcuC increased fumarate-succinate exchange and fumarate uptake by DcuA and DcuB, suggesting a…

Fumarate dependent protein composition under aerobic and anaerobic growth conditions in Escherichia coli

2020

Abstract In the absence of sugars, C4-dicarboxylates (C4DC) like fumarate represent important substrates for growth of Escherichia coli. Aerobically, C4DCs are oxidized to CO2 whereas anaerobically, C4DCs are used for fumarate respiration. In order to determine the impact of fumarate under aerobic and anaerobic conditions, proteomes of E. coli W3110 grown aerobically or anaerobically with fumarate and/or the non-C4DC substrate glycerol were comparatively profiled by nanoLC-MS/MS. Membrane enrichment allowed sensitive detection of membrane proteins. A total of 1657 proteins of which 646 and 374 were assigned to the cytosol or membrane, respectively, were covered. Presence of fumarate trigger…

P2‐307: A stable G‐quadruplex within the ADAM10 5'‐UTR is involved in translational repression of ADAM10

2011

Fine analysis of the chromatin structure of the yeast SUC2 gene and of its changes upon derepression. Comparison between the chromosomal and plasmid-…

1987

Micrococcal nuclease digestion has been used to investigate some fine details of the chromatin structure of the yeast SUC2 gene for invertase. Precisely positioned nucleosomes have been found on a 2 kb sequence from the 3' non-coding region, and four nucleosomes also seem to occupy fixed positions on the 5' flank. Eleven nucleosomes lie on the coding region, although their positioning is not as precise as in the flanks. When the gene is derepressed, these latter nucleosomes adopt a more open conformation and so do two of the nucleosomes positioned on the 5' flank. A dramatic change occurs in the 3' flank, whose involvement in the structural transitions of chromatin upon gene activation is p…

Global translational repression induced by iron deficiency in yeast depends on the Gcn2/eIF2α pathway

2020

Iron is an essential element for all eukaryotic organisms because it participates as a redox active cofactor in a wide range of biological processes, including protein synthesis. Translation is probably the most energy consuming process in cells. Therefore, one of the initial responses of eukaryotic cells to stress or nutrient limitation is the arrest of mRNA translation. In first instance, the budding yeast Saccharomyces cerevisiae responds to iron deficiency by activating iron acquisition and remodeling cellular metabolism in order to prioritize essential over non-essential iron-dependent processes. We have determined that, despite a global decrease in transcription, mRNA translation is a…

A short-range gradient of histone H3 acetylation and Tup1p redistribution at the promoter of the Saccharomyces cerevisiae SUC2 gene.

2003

Chromatin immunoprecipitation assays are used to map H3 and H4 acetylation over the promoter nucleosomes and the coding region of the Saccharomyces cerevisiae SUC2 gene, under repressed and derepressed conditions, using wild type and mutant strains. In wild type cells, a high level of H3 acetylation at the distal end of the promoter drops sharply toward the proximal nucleosome that covers the TATA box, a gradient that become even steeper on derepression. In contrast, substantial H4 acetylation shows no such gradient and extends into the coding region. Overall levels of both H3 and H4 acetylation rise on derepression. Mutation of GCN5 or SNF2 lead to substantially reduced SUC2 expression; in…