Question

What role do insulator sequences play in the regulation of eukaryotic transcription?

1) They block binding of transcription repressors to cis-acting promoter elements.
2) They block binding of transcription factors to cis-acting promoter elements.
3) They block communication between enhancers and nontargeted promoters.
4) They block binding of transcription factors to enhancers.

Answer 1

Insulator sequences play a role in the regulation of eukaryotic transcription by blocking communication between enhancers and non-targeted promoters. The correct option is 3) They block communication between enhancers and nontargeted promoters.

Step-by-step explanation:

Insulator sequences play a role in the regulation of eukaryotic transcription by blocking communication between enhancers and non-targeted promoters. They prevent the activation of genes when the enhancers are not supposed to interact with the promoters. Insulator sequences help maintain the specificity of gene regulation by keeping enhancers from influencing the expression of genes that are located far away on the chromosome.

For example, if an enhancer is located between two genes A and B, an insulator sequence can be present between the enhancer and gene A to prevent the enhancer from activating gene A. This ensures that the enhancer only activates gene B and not gene A.

In summary, insulator sequences act as barriers that prevent enhancers from affecting the expression of non-targeted genes, thus maintaining the specificity of gene regulation. The correct option is 3) They block communication between enhancers and nontargeted promoters.