repressor


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Related to repressor: repressor gene, Lac repressor

repressor:

see nucleic acidnucleic acid,
any of a group of organic substances found in the chromosomes of living cells and viruses that play a central role in the storage and replication of hereditary information and in the expression of this information through protein synthesis.
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Repressor

 

a special regulating protein formed in bacterial cells that halts transcription, which is the synthesis of messenger ribonucleic acid (m-RNA) from a specific operon (a group of genes that carry out the synthesis of functionally related enzymes). The number of different repressors corresponds to the number of operons.

Unlike other proteins, a repressor present in a cell consists of ten to 20 molecules. The synthesis of m-RNA ceases when a repressor combines with an operator, which is the regulating part of an operon. An effector, for example, lactose in a lactose operon, interacts with a repressor to form a complex that inactivates and produces a reversible spatial change in a repressor molecule. This type of repressor can no longer combine with an operator and, as a result, m-RNA synthesis resumes.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

repressor

[ri′pres·ər]
(biochemistry)
An end product of metabolism which represses the synthesis of enzymes in the metabolic pathway.
(genetics)
The product of a regulator gene that acts to repress the transcription of another gene.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
The main goal of this project was to initiate a structure-function study on the repressor protein of phage [epsilon]34.
Concomitant with the decrease in CD4+ T cell-derived proinflammatory cytokine production, the frequency of key repressor IL10 was significantly increased in septic mice at 30 h compared to sham (Figure 2(d); sham = 2.14 [+ or -] 0.12%, CLP = 2.92 [+ or -] 0.1%; p = 0.0011).
However, there may be a bacterial example in the most classical of systems, the lac repressor [78, 79].
To further check that the mutant has the ability to overexpress the xylanase gene in the presence of glucose or not, both wild type and mutant strains were grown in the presence of xylan as carbon source plus glucose as repressor in the culture medium.
The NSrR gene is a major transcriptional repressor in response to iron and also a negative regulator of motility [64-66].
Typically, genes responsible for gluconate uptake are organized into an operon under negative control of the GntR repressor [25] (see Figure 1).
Steinmann, V Plaisance et al., "The transcriptional repressor REST determines the cell-specific expression of the human MAPK8IP1 gene encoding IB1 (JIP-1)," Molecular and Cellular Biology, vol.
According to Salama, her team's findings support the idea that expansion of this family of repressor genes occurred in response to waves of retrotransposon activity.
These results suggest that Chrono functions as a core clock repressor, Toru Takumi from RIKEN added.
coli, gabC (formerlyygaE) was reported to belong to the gabDTPC operon, and gabC is the repressor of the operon [21].
Citation: "mTORCl Targets the Translational Repressor 4E-BP2, but Not S6 Kinase 1/2, to Regulate Neural Stem Cell Self-Renewal In Vivo"; Nathaniel W.