During initiation of transcription, which event typically occurs first?

• A. Transcription factors bind at the TATA box promoter
• B. RNA polymerase detaches from the DNA
• C. DNA replicates
• D. RNA is released from the transcription complex

Answer: (A)

The first step in transcription initiation is transcription factors binding to the promoter at the TATA box. This initial binding sets up the transcription initiation complex and recruits RNA polymerase II, allowing the DNA to unwind and transcription to begin. Without this promoter recognition by transcription factors, RNA polymerase can’t properly assemble at the start site, so initiation can’t proceed.

The other events happen later in the process: DNA replication is a separate process, not part of transcription initiation; RNA release from the complex occurs after transcription has progressed and typically at termination; and RNA polymerase detaches after transcription is finished, not at the very start.