Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

MlcR is a pathway-specific transcriptional activator of the ML-236B biosynthetic genes in Penicillium citrinum. The MlcR-binding sequences were identified by an in vitro gel-shift assay and an in vivo reporter assay for the region between mlcA and mlcC as a model. The gel-shift assay showed that recombinant MlcR bound to the DNA sequence 5'-ACGGCGTTATTCGG-3' and most of the bases in this motif were required for the interaction between MlcR and DNA. In the reporter assay using beta-glucuronidase (GUS), substitution of the bases in this binding sequence resulted in the drastic reduction of GUS activities. These data clearly indicate that this MlcR-binding sequence is essential for the transcriptional activation of mlcA and mlcC in P. citrinum. Similar motifs were found in other loci of the ML-236B biosynthetic gene cluster and the consensus-binding motif for MlcR was predicted to be a direct repeat, 5'-WCGG-N(6)-TCGG-3'.
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PMID:Identification of the specific sequence recognized by Penicillium citrinum MlcR, a GAL4-type transcriptional activator of ML-236B (compactin) biosynthetic genes. 1866 69

Aux/IAA proteins are proposed to be transcriptional repressors that play a crucial role in auxin signaling by interacting with auxin response factors and repressing early/primary auxin response gene expression. In assays with transfected protoplasts, this repression was previously shown to occur when auxin concentrations in a cell are low, and derepression/activation was observed when auxin concentrations are elevated. Here we show that a stabilized version of the Arabidopsis (Arabidopsis thaliana) IAA17 repressor, when expressed constitutively or in a specific cell type in Arabidopsis plants, confers phenotypes similar to plants with decreased auxin levels. In contrast, a stabilized version of IAA17 that was converted to a transcriptional activator confers phenotypes similar to plants with increased auxin levels, when expressed under the same conditions in Arabidopsis plants. Free auxin levels were unchanged compared to control (DR5:beta-glucuronidase), however, in the seedlings expressing the IAA17 repressor and activator. These results together with our previous results carried out in transfected protoplasts suggest that the hormone auxin can be bypassed to regulate auxin signaling in a cell-autonomous manner in plants.
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PMID:Constitutive repression and activation of auxin signaling in Arabidopsis. 1912 21

Quorum sensing (QS) plays important roles in the pathogenicity of Burkholderia glumae, the causative agent of bacterial rice grain rot. We determined how QS is involved in catalase expression in B. glumae. The QS-defective mutant of B. glumae exhibited less catalase activity than wild-type B. glumae. A beta-glucuronidase assay of a katG::Tn3-gusA78 reporter fusion protein revealed that katG expression is under the control of QS. Furthermore, katG expression was upregulated by QsmR, a transcriptional activator for flagellar-gene expression that is regulated by QS. A gel mobility shift assay confirmed that QsmR directly activates katG expression. The katG mutant produced toxoflavin but exhibited less severe disease than BGR1 on rice panicles. Under visible light conditions and a photon flux density of 61.6 micromol(-1) m(-2), the survival rate of the katG mutant was 10(5)-fold lower than that of BGR1. This suggests that KatG is a major catalase that protects bacterial cells from visible light, which probably results in less severe disease caused by the katG mutant.
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PMID:The quorum sensing-dependent gene katG of Burkholderia glumae is important for protection from visible light. 1939 81

Transduction of glucose (Glc) signaling is critical for plant development, metabolism, and stress responses. However, identifying initial Glc sensing and response stimulating mechanisms in plants has been difficult due to dual functions of glucose as energy sources and signaling component. A basic Helix-Loop-Helix 104 (bHLH104) protein is a homolog of bHLH34 previously isolated from Arabidopsis that functions as a transcriptional activator of Glc and abscisic acid (ABA) responses. In this study, we characterized bHLH104 as a transcription factor that binds to the regulatory region of Arabidopsis Plasma membrane Glc-responsive Regulator (AtPGR) gene. The bHLH104 binds to 5'-AANA-3' element of the promoter region of AtPGR in vitro and represses beta-glucuronidase (GUS) activity in AtPGR promoter-GUS transgenic plants. Genetic approaches show that bHLH104 positively regulates Glc and abscisic acid (ABA) response. These results suggest that bHLH104 is involved in Glc- and ABA-mediated signaling pathway. Taken together, these findings provide evidence that bHLH104 is an important transcription regulator in plant-sensitivity to Glc and ABA signaling.
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PMID:A basic helix-loop-helix 104 (bHLH104) protein functions as a transcriptional repressor for glucose and abscisic acid signaling in Arabidopsis. 3063 20


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