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Multiple Choice
Which of the following is an example of a cis-acting element in eukaryotic transcription?
A
RNA polymerase
B
Enhancer
C
Mediator complex
D
Transcription factor
Verified step by step guidance
1
Understand the concept of cis-acting elements: Cis-acting elements are regions of non-coding DNA which regulate the transcription of nearby genes. They are typically located on the same molecule of DNA as the gene they regulate.
Identify the role of enhancers: Enhancers are a type of cis-acting element. They are sequences of DNA that can increase the rate of transcription of a gene. Enhancers can be located upstream, downstream, or even within the gene they regulate.
Differentiate between cis-acting and trans-acting elements: Trans-acting elements, such as transcription factors and RNA polymerase, are proteins that bind to cis-acting elements to regulate gene expression. They are not part of the DNA sequence itself.
Evaluate the options given: RNA polymerase and transcription factors are trans-acting elements because they are proteins that interact with DNA to regulate transcription. The mediator complex is also a protein complex involved in transcription regulation.
Conclude that the enhancer is the correct example of a cis-acting element: Since enhancers are DNA sequences that regulate transcription from the same molecule of DNA, they fit the definition of cis-acting elements.