Question

Eukaryotic promoters generally contain three regions: the core promoter, the regulatory promoter, and distant sequences. Both the regulatory promoter and distant sequences usually contain DNA sequences called enhancers. The function of the enhancers is to bind activator proteins. Once they are bound, what is the function of the activators? (2)

Some distant enhancer sequences can be thousands of bases away from the core promoter. How are the activator proteins they bind able to influence the core promoter at such distances? (2)

Answer 1

Question 1

Answer: Activators are proteins that binds to enhancers and function to increase the expression of genes by interacting with transcription factors and RNA polymerase at the promoter region.

Question 2

Answer: Activators binds to enhancers sequences that are present far away from the core promoter. A DNA bending protein binds near to enhancer change the shape of DNA by bending it. This leads to interaction of activators bound to enhancer with the transcription factors bound to promoter, leading to recruitment of RNA polymerase to initiate gene expression. In this way, enhancer sequences that is present far away from the core promoter fold over and allow the activator to interact with core promoter region, leading to activation of gene expression.