Which of the following is true about enhancer DNA sequences in gene regulation?

• A. Enhancer sequences directly bind to RNA polymerase to initiate transcription.
• B. Enhancer sequences are always located immediately upstream of the gene they regulate.
• C. Enhancer sequences are located only within the promoter region of a gene.
• D. Enhancer sequences can increase the transcription of associated genes.

Answer: (D)

Verified step by step guidance

1. Understand the role of enhancer sequences: Enhancer sequences are DNA elements that can increase the transcription of associated genes by interacting with specific proteins called transcription factors.
2. Recognize the location flexibility of enhancers: Enhancer sequences can be located upstream, downstream, or even within introns of the gene they regulate, not just immediately upstream or within the promoter region.
3. Clarify the interaction with RNA polymerase: Enhancers do not directly bind to RNA polymerase. Instead, they interact with transcription factors, which in turn help recruit RNA polymerase to the promoter region.
4. Identify the correct statement: Among the given options, the statement that 'Enhancer sequences can increase the transcription of associated genes' accurately describes the function of enhancers in gene regulation.
5. Summarize the function of enhancers: Enhancers are crucial for regulating gene expression by increasing the likelihood of transcription, often through complex interactions with transcription factors and other regulatory proteins.