Question

TATA-less promoters do not contain a recognizable TATA box but are still associated with TBP. What features are often found in these promoters?

Short answer

Answer: Common features in TATA-less promoters include the Initiator (Inr) element, Downstream promoter element (DPE), TFIIB recognition element (BRE), and CpG islands. These elements play crucial roles in transcription initiation and regulation despite the absence of a TATA box.

Step-by-step solution

Briefly explain TATA-less promoters

TATA-less promoters are a type of promoter sequence in eukaryotes that lack the traditional TATA box - a conserved DNA sequence that serves as the binding site for the TATA-binding protein (TBP) and helps initiate transcription. Despite the absence of a TATA box, TATA-less promoters still associate with the TBP and effectively initiate transcription.

Describe characteristics of TATA-less promoters

The following features are often found in TATA-less promoters: - Initiator (Inr) element: This is a core promoter element which surrounds the transcription start site (TSS) and plays a crucial role in transcription initiation. - Downstream promoter element (DPE): This element is located around 30 base pairs downstream of the TSS and recruits TFIID, a crucial subunit of the general transcription factor complex. - TFIIB recognition element (BRE): This is another core promoter element that is found upstream of the TSS and serves as the binding site for the transcription factor IIB (TFIIB). - CpG islands: DNA regions with a high frequency of CpG dinucleotide sequences are commonly found in TATA-less promoters of housekeeping genes, which are essential for cellular processes and are expressed at a constant level.

Summarize

TATA-less promoters are promoter sequences that lack a TATA box but remain associated with the TATA-binding protein. Key features of TATA-less promoters often include the Initiator (Inr) element, Downstream promoter element (DPE), TFIIB recognition element (BRE), and CpG islands – all of which contribute to transcription initiation and regulation.