Which molecule signals the end of transcription in the RNA synthesis process?

The molecule that signals the end of transcription in the RNA synthesis process is the terminator. In the context of transcription, the terminator is a specific sequence of nucleotides in the DNA that indicates where RNA synthesis should stop. When RNA polymerase encounters this sequence, it recognizes it as a signal to detach from the DNA template and release the newly synthesized RNA molecule. This process is crucial because it ensures that only the intended portions of the DNA are transcribed into RNA, allowing the synthesis of a functional gene product.

The promoter, in contrast, is a region of DNA that initiates the transcription process but does not signal its end. Transcription factors are proteins that help regulate transcription by assisting RNA polymerase in recognizing and binding to the promoter, but they do not mark the termination of transcription. Introns are non-coding segments of a gene that are transcribed into RNA but are typically spliced out before the RNA molecule is translated into a protein; they do not play a role in signaling the end of transcription. Understanding the roles of each of these molecules helps clarify how transcription is regulated and terminated effectively.