What are the general steps of transcription?
Posted June 22, 2020
- Initiation: The enzyme RNA polymerase, together with the general transcription factors, bind to a specific DNA sequence called the promoter, which signals the double-stranded DNA to unwind and create an initiation bubble. RNA polymerase adds the first extending NTP to an initiating NTP, yielding an initial RNA product.
- Elongation: RNA polymerase uses one strand of the DNA (noncoding strand) as the template to build the RNA molecule using complementary base pairs. The RNA molecule produced carries the same genetic information of the coding strand except that thymines are replaced with uracils. Multiple rounds of transcription may occur in this step so that many copies of a gene can be produced.
- Termination: Termination is the final step of transcription, when the sequences called terminators signal the completeness of RNA transcript. The newly synthesized mRNA strand is then released from the elongation complex.