Question

TATA box of eukaryotic promoter lies
A. About 25 bp upstream of the transcription start site
B. About 50 bp upstream of the transcription start site
C. About 75 bp upstream of the transcription start site
D. About 200 bp upstream of the transcription start site

Answer 1

The promoter can be defined as a sequence of DNA to which proteins are bonded and it initiates the transcription of a single RNA from the DNA downstream of it. This RNA may encode a protein. Promoters are found near the transcription start sites of genes, upstream on the DNA.

Complete answer:
The TATA box can be defined as a successive order of DNA that is present in the core promoter region of genes in archaea and eukaryotes. It is also known as the Goldberg-Hogness box. In the bacterial gene, the homolog of the TATA box is known as the Pribnow box. It is a shorter consensus sequence.
The TATA box can be considered as a non-coding DNA sequence. It is also called a cis-regulatory element. It was called the TATA box because there is a consensus sequence that is characterized by repeating T and A base pairs of DNA.
The TATA box was first found in the year 1978 and it is found as a component of eukaryotic promoters. Transcription is introduced at the TATA box in TATA-containing genes. The TATA box acts as the binding site of the TATA-binding protein or TBP and other transcription factors in some eukaryotic genes.
Transcription is a process that synthesizes an RNA molecule from a DNA sequence. In the eukaryotic genes, TATA box is present which is located 25-35 base pairs before the transcription start site of a gene. The TATA box can identify the direction of transcription and also points out the DNA strand to be read. Proteins which are known as transcription factors can bind to the TATA box and recruit an enzyme that is known as RNA polymerase, which synthesizes RNA from DNA. The gene transcription that takes place by RNA polymerase II depends on the regulation of the core promoter by long-range regulatory elements such as enhancers and silencers.

Hence, the correct answer is option (A).

Note: A TATA box is a sequence of DNA. The TATA box points out where a genetic sequence can be read and decoded. It is a type of promoter sequence. TATA box defines the site where the transcription begins to other molecules. The location of promoter sequences may vary between bacteria and eukaryotes. In eukaryotes, the TATA box is found 25 base pairs upstream of the transcription start site.