Which component is essential for initiation of transcription in eukaryotes but not in prokaryotes?

Which component is essential for initiation of transcription in eukaryotes but not in prokaryotes?

• A. RNA polymerase II
• B. A sigma factor
• C. Transcription factors and promoter elements such as TATA box
• D. A primer

Answer: (C)

In eukaryotes, starting transcription isn’t just about the RNA polymerase II enzyme; it requires a group of general transcription factors that recognize promoter DNA and assemble with RNA polymerase II to form the preinitiation complex. Promoter elements like the TATA box act as landing pads for these factors, helping to properly position and unwind the DNA so transcription can begin. This combination of transcription factors and promoter elements is what uniquely enables initiation in eukaryotes, and it’s different from prokaryotes, where a sigma factor bound to the RNA polymerase suffices to recognize promoters. A primer is related to DNA replication, not transcription. So the essential component here is the transcription factors and promoter elements such as the TATA box.

In eukaryotes, starting transcription isn’t just about the RNA polymerase II enzyme; it requires a group of general transcription factors that recognize promoter DNA and assemble with RNA polymerase II to form the preinitiation complex. Promoter elements like the TATA box act as landing pads for these factors, helping to properly position and unwind the DNA so transcription can begin. This combination of transcription factors and promoter elements is what uniquely enables initiation in eukaryotes, and it’s different from prokaryotes, where a sigma factor bound to the RNA polymerase suffices to recognize promoters. A primer is related to DNA replication, not transcription. So the essential component here is the transcription factors and promoter elements such as the TATA box.