Question

Protooncogenes produce products that have specific roles in regulating growth and differentiation of normal cells. Mutations can turn these genes into oncogenes whose products are less responsive to normal control. Unmutated protein \(\mathrm{p} 53,\) a tumor suppressor, is a transcription factor, inhibiting some genes and activating others. P53 inhibits genes with TATA sequences and activates genes for DNA repair. The TATA sequence A. occurs about 25 bp downstream from the start of transcription. B. binds directly to RNA polymerase. C. binds transcription factors which bind RNA polymerase. D. binds p53. E. is an enhancer sequence.

Short answer

Answer: The TATA sequence binds transcription factors which bind RNA polymerase.

Step-by-step solution

Understand the roles of p53 and transcription factors.

The p53 tumor suppressor protein is a transcription factor that inhibits some genes and activates others. Transcription factors, including p53, are proteins that help control the expression of other genes by binding to specific sequences on DNA.

Analyze the given options.

Let us go through each option and analyze them to find the correct answer: A. The TATA sequence occurs about 25 bp downstream from the start of transcription. - Incorrect. The TATA sequence occurs about 25 to 30 bp upstream of the transcription initiation site. B. The TATA sequence binds directly to RNA polymerase. - Incorrect. The TATA sequence does not directly bind to RNA polymerase. C. The TATA sequence binds transcription factors which bind RNA polymerase. - Correct. The TATA sequence binds transcription factors like TATA-binding protein (TBP), which in turn recruits RNA polymerase. D. The TATA sequence binds p53. - Incorrect. p53 acts as a transcription factor, but it does not directly bind to the TATA sequence. It generally binds to different consensus sequences on the target genes. E. The TATA sequence is an enhancer sequence. - Incorrect. The TATA sequence is not an enhancer sequence but rather a promoter element, playing a role in the initiation of transcription.

Choose the correct answer.

The correct answer is option C: The TATA sequence binds transcription factors which bind RNA polymerase.