Question

During transcription, holoenzyme RNA polymerase binds to DNA sequence and DNA assumes a saddle like structure at that point. The sequence is called as
A. AAAT box
B. TATA box
C. GGCC box
D. CAAT box

Answer 1

Hint: In order to begin transcribing a gene, RNA polymerase binds to the DNA of the gene in a region called the promoter. Basically, the promoter informs the polymerase where to sit on the DNA and start transcribing.

Complete Answer:
- The TATA box is a DNA sequence which specifies where a genetic sequence can be read and decoded. It is a sequence of promoters that leads to the initiation of the transcription process.
- The TATA box is named for its preserved DNA sequence, most commonly known as TATAAA. Many eukaryotic genes have a retained TATA box located 25-35 base pairs prior to gene transcription.
- The TATA box is capable of deciding the transcription direction and also reveals the DNA string to be read. The TATA box is recognized either by the TATA-binding protein or by the TBP.
- The TBP binds the TATA box directly by folding its DNA binding domain into a semi-symmetric saddle shape with the DNA between the two sides of the saddle.

Option B is therefore the correct answer.

Note: RNA polymerase II holoenzyme (a catalytic active enzyme consisting of an apoenzyme combined with its cofactor) is a type of eukaryotic RNA polymerase II that is recruited to promote protein-coding genes in living cells. It consists of RNA polymerase II which is a subset of regulatory proteins called SRB proteins.