Steps of Transcription - Initiation

Question 1

Step 1 - Initiation

Answer 1

TBP domain of TFIID binds TATA box which facilitates TFIIB binding next to it.

Question 2

Step 2 - initiation

Answer 2

TFIID:TFIIB recruited TFIIE, TFIIH and RNA polymerase

Question 3

Step 3 - initiation

Answer 3

TFIIH acts as a helicase at START site of DNA and phosphorylates the 5th serine of the RNA polymerase C-terminal domain (CTD) repeat sequence which changes the polymerase conformation and recruits capping proteins to this domain.

Question 4

Step 4 - initiation

Answer 4

TFs are released

Question 5

Step 5 - initiation

Answer 5

RNA polymerase leave promoter region to begin elongation.

Question 6

What is the C-terminal Domain and why is it present in RNA Polymerase?

Answer 6

This is a domain containing 52, 7 amino acid tandem repeats that each contain two serines. It is there to extend the core structure of the polymerase.