What is the role of enhancer sequences in the transcription of eukaryotic genes?

• A. Enhancer sequences directly bind to RNA polymerase to initiate transcription.
• B. Enhancer sequences inhibit transcription by blocking promoter regions.
• C. Enhancer sequences are involved in the splicing of pre-mRNA.
• D. Enhancer sequences increase the rate of transcription by binding transcription factors.

Answer: (D)

Verified step by step guidance

1. Understand that enhancer sequences are DNA elements that play a crucial role in the regulation of gene expression in eukaryotic cells.
2. Recognize that enhancer sequences do not directly bind to RNA polymerase. Instead, they function by interacting with specific proteins known as transcription factors.
3. Learn that when transcription factors bind to enhancer sequences, they facilitate the assembly of the transcription machinery at the promoter region, thereby increasing the rate of transcription.
4. Note that enhancer sequences can be located at varying distances from the promoter they regulate, sometimes even thousands of base pairs away, and can function in an orientation-independent manner.
5. Clarify that enhancer sequences do not inhibit transcription or involve themselves in the splicing of pre-mRNA. Their primary role is to enhance the transcription of specific genes by increasing the efficiency of transcription initiation.