What occurs during the transcription initiation phase?

During the transcription initiation phase, transcription factors bind to the promoter region of the DNA. This binding is crucial as it helps to recruit RNA polymerase to the promoter, facilitating the start of transcription. The transcription factors are proteins that assist in the recognition of the promoter sequence, ensuring that transcription begins at the correct location on the DNA strand.

They form a complex that stabilizes the interaction between RNA polymerase and the DNA. Once RNA polymerase is properly positioned at the promoter, it can then start synthesizing RNA based on the DNA template. This process is essential for gene expression, as it marks the first step in converting the genetic code from DNA into a functional RNA molecule, which will later be translated into proteins.

The other options do not accurately describe what happens during the transcription initiation phase; for instance, RNA polymerase detaching occurs at termination, intron removal happens during RNA processing, and mRNA exiting the nucleus occurs after transcription and processing are complete.