How does transcription inhibition differ between prokaryotes and eukaryotes? Describe the two mechanisms used by eukaryotes to direct the enhancers toward certain promoters and away from others

What will be an ideal response?


Prokaryotes typically use a repression mechanism in which repressor proteins inhibit transcription by binding to operator sequences that overlap promoters. This blocks the binding of RNA polymerase, thus inhibiting the gene or operon.
In eukaryotes, this mechanism of transcription inhibition is not seen. Instead, eukaryotic repressors inhibit transcription through other mechanisms.
1. Eukaryotic repressors can bind to silencer sequences, cis-acting regulatory sequences that block transcription by directly preventing enhancer-mediated transcription. For example, yeast use the proteins Mig1 and Tup1 to bind to the silencer site when glucose is present, thus inhibiting transcription of the galactose utilization pathway.

2. Eukaryotic insulator sequences can block the action of the enhancer. Insulators are cis-acting sequences located between enhancers and promoters of genes that are to be insulated from the effects of the enhancer. Insulators direct enhancers to interact with the intended promoter and block communication between enhancers and other promoters. This mechanism likely involves allowing the formation of DNA loops containing enhancers and their intended promoter targets while preventing the formation of DNA loops containing an enhancer and a promoter that is not its intended target.

Biology & Microbiology

You might also like to view...

The equilibrium constant for complex formation between molecules A and B will depend on their relative concentrations, as well as the rates at which the molecules associate and dissociate

The association rate will be larger than the dissociation rate when complex formation is favorable. The energy that drives this process is referred to as ___________. (a) dissociation energy. (b) association energy. (c) binding energy. (d) releasing energy.

Biology & Microbiology

Each amino acid is encoded by only one mRNA codon

a. True b. False Indicate whether the statement is true or false

Biology & Microbiology

Which statement is true regarding pasteurization?

A. During pasteurization, the heating is done very quickly to prevent a change in the integrity and taste of the product.  B. It does not kill all microorganisms in milk. C. The process was first used in the wine industry. D. All statements are true.

Biology & Microbiology

You work for a company that manufactures food products. A new "wonder food" is being distributed by a rival company. The researchers in your company determine that the "wonder food" contains only carbon, oxygen, and hydrogen. At this point, your

researchers can say with certainty that the food A) includes proteins. B) could only be made of triglycerides. C) could only be made of carbohydrates. D) does not include proteins or nucleic acids.

Biology & Microbiology