Which of the following is not involved in the formation of a eukaryotic transcription initiation complex?

Options

A. Transcription factors
B. snRNA
C. RNA polymerase-II
D. Promoter

Answer

To solve the question "Which of the following is not involved in the formation of a eukaryotic transcription initiation complex?", we will analyze each option provided and determine their roles in the transcription initiation process.

### Step-by-Step Solution:

1. **Understand the Components of the Transcription Initiation Complex**:
- The transcription initiation complex in eukaryotes is formed primarily in the nucleus and involves several key components.

2. **Identify the Key Players**:
- **Transcription Factors**: These are proteins that bind to specific DNA sequences in the promoter region to initiate transcription.
- **RNA Polymerase II**: This enzyme is responsible for synthesizing mRNA from the DNA template during transcription.
- **Promoter**: This is a specific DNA sequence where RNA polymerase and transcription factors bind to initiate transcription.
- **Small Nuclear RNA (snRNA)**: These are involved in the processing of pre-mRNA, particularly in splicing.

3. **Analyze Each Option**:
- **Transcription Factors**: Involved in recognizing the promoter and recruiting RNA polymerase II.
- **RNA Polymerase II**: Directly involved in synthesizing mRNA and is a crucial part of the initiation complex.
- **Promoter**: Essential for the binding of transcription factors and RNA polymerase II.
- **snRNA**: While important for mRNA processing, it does not play a role in the formation of the transcription initiation complex.

4. **Conclusion**:
- Since snRNA is not involved in the formation of the transcription initiation complex, the correct answer is **snRNA**.

### Final Answer:
**snRNA** is not involved in the formation of a eukaryotic transcription initiation complex.

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