Where does the assembly of transcription factors begin?

Where does the assembly of transcription factors begin?

• A. Downstream from the transcription start site
• B. Upstream from the transcription start site
• C. At the terminator
• D. Within the coding region

Answer: (B)

Initiation of transcription relies on assembling transcription factors at the promoter, which sits on the DNA just upstream of where RNA synthesis begins. The promoter contains specific DNA elements that transcription factors recognize, and this assembly forms the pre-initiation complex with RNA polymerase II ready to start. Because transcription starts at the transcription start site, the machinery must bind on the DNA immediately before that site—upstream of it. Downstream regions like the coding sequence or the terminator are part of the transcribed gene or signal termination, not the starting point for assembly.

Initiation of transcription relies on assembling transcription factors at the promoter, which sits on the DNA just upstream of where RNA synthesis begins. The promoter contains specific DNA elements that transcription factors recognize, and this assembly forms the pre-initiation complex with RNA polymerase II ready to start. Because transcription starts at the transcription start site, the machinery must bind on the DNA immediately before that site—upstream of it. Downstream regions like the coding sequence or the terminator are part of the transcribed gene or signal termination, not the starting point for assembly.