Which promoter element is commonly found in many eukaryotic genes and helps recruit transcription factors?

Which promoter element is commonly found in many eukaryotic genes and helps recruit transcription factors?

• A. CAAT box
• B. Pribnow box
• C. Lac operator
• D. TATA box and transcription factor binding sites

Answer: (D)

In eukaryotes, turning on a gene requires transcription factors to assemble at the promoter to recruit RNA polymerase II. The TATA box, located about 25–30 bases upstream of the start site, is a classic promoter element that is recognized by TBP, a subunit of TFIID, helping to recruit the general transcription machinery. In addition, transcription factor binding sites in promoter regions attract specific activators or coactivators that further stabilize the preinitiation complex and boost transcription. So, the combination of a TATA box and transcription factor binding sites provides the strongest, most general mechanism for recruiting transcription factors across many eukaryotic genes. The other options point to elements found in prokaryotes or are only part of the picture; the Pribnow box is a bacterial promoter element, the Lac operator is a repressor binding site in bacteria, and while the CAAT box is a promoter element, it doesn’t alone capture the broad recruitment role described by the TATA box plus transcription factor binding sites.

In eukaryotes, turning on a gene requires transcription factors to assemble at the promoter to recruit RNA polymerase II. The TATA box, located about 25–30 bases upstream of the start site, is a classic promoter element that is recognized by TBP, a subunit of TFIID, helping to recruit the general transcription machinery. In addition, transcription factor binding sites in promoter regions attract specific activators or coactivators that further stabilize the preinitiation complex and boost transcription. So, the combination of a TATA box and transcription factor binding sites provides the strongest, most general mechanism for recruiting transcription factors across many eukaryotic genes. The other options point to elements found in prokaryotes or are only part of the picture; the Pribnow box is a bacterial promoter element, the Lac operator is a repressor binding site in bacteria, and while the CAAT box is a promoter element, it doesn’t alone capture the broad recruitment role described by the TATA box plus transcription factor binding sites.