Transcription -- Movie Narrative (Advanced Look)
Transcription is the process of making RNA from a DNA template. Several key factors are involved in this process. Including, DNA, transcription factors, RNA polymerase, and ATP.
Transcription begins with a strand of DNA. It is divided into several important regions. The largest of these is the transcription unit. This portion of the DNA will be used to produce RNA. Upstream of the transcription unit is the TATA box. An enhancer region may also be involved.
Several complexes, known as transcription factors, are required for successful transcription. The first is TFIID, the largest of the general factors. A component of this factor, TBP, binds to the DNA using the TATA box to position TFIID near the transcription initiation site. Other transcription factors, including TFIIA and TFIIB, then attach.
These complexes prepare the DNA for the successful binding of RNA polymerase. One RNA polymerase is bound, other transcription factors complete the mature transcription complex.
Now, energy must be added to the system for transcription to begin. This energy is provided by the reduction of ATP into ADP and Pi.
RNA polymerase then synthesizes an RNA template from the strand of DNA. Most factors are released after transcription begins. When the end of the transcription unit is reached, the RNA polymerase dissociates, and the newly formed strand of RNA is released.