What are activators and repressors?
Activators (and sometimes inducers) instigate positive regulation, and repressors instigate negative regulation. When a repressor binds to an operon, the transcription process is slowed or halted.
What are repressors in gene regulation?
A repressor is a protein that has a negative effect on gene expression. So these usually are proteins that bind to DNA, and they either prevent the RNA transcription machinery from getting in there and transcribing that DNA, or they just slow it down.
What are bacterial activators and repressors?
Repressors are proteins that suppress transcription of a gene in response to an external stimulus, whereas activators are proteins that increase the transcription of a gene in response to an external stimulus.
What is the activator in gene regulation?
A transcriptional activator is a protein (transcription factor) that increases transcription of a gene or set of genes. Activators are considered to have positive control over gene expression, as they function to promote gene transcription and, in some cases, are required for the transcription of genes to occur.
What is positive gene regulation?
Positive gene regulation is the stage of gene expression that enables to proceed gene expression. Normally, it occurs through the binding of the activator proteins called transcription factors to the promoter region of the gene. Generally, the resultant complex interacts with RNA polymerase, initiating transcription.
Why is it advantageous for bacteria to have operons?
By providing the means to produce proteins only when and where they are required, the operon allows the cell to conserve energy (which is an important part of an organism’s life strategy).
How are activators and repressors involved in gene regulation?
Activators and repressors are the two types of transcription factors involved in the regulation of gene expression at the transcription level. Activators bind to the enhancer regions in the DNA and facilitate the binding of RNA polymerase to the promoter.
What’s the difference between a repressor and an activator?
Repressors are proteins that suppress transcription of a gene in response to an external stimulus, whereas activators are proteins that increase the transcription of a gene in response to an external stimulus.
What is the definition of a repressor protein?
: one that represses especially : a protein that is determined by a regulatory gene, binds to a genetic operator, and inhibits the initiation of transcription of messenger RNA.
What is the role of repressors in the regulation of transcription?
The regulation of transcription by repressors as well as by activators considerably extends the range of mechanisms that control the expression of eukaryotic genes. One important role of repressors may be to inhibit the expression of tissue-specific genes in inappropriate cell types.