Question

Phosphorylation of the C-terminal domain of eukaryotic RNA polymerase inhibits interaction with what protein, thus allowing the polymerase to leave the promoter?

a) TFIIB
b) TFIID
c) TFIIE
d) TFIIH

Answer 1

Phosphorylation of RNA polymerase II's C-terminal domain inhibits its interaction with TFIIB, allowing the enzyme to transition from initiation to elongation during transcription.

Step-by-step explanation:

The process of phosphorylation of the C-terminal domain of eukaryotic RNA polymerase II plays a pivotal role in the transition from initiation to elongation during transcription. This modification inhibits interaction with TFIIB, thus allowing the polymerase to leave the promoter and begin mRNA synthesis. Following the formation of the preinitiation complex, which includes various transcription factors like TFIID, TFIIE, TFIIF, and TFIIH, RNA polymerase II is recruited and associates with the DNA. Phosphorylation of the RNA polymerase II triggers the release of TFIIB from the preinitiation complex, thereby releasing the RNA polymerase to commence elongation. This step is crucial as it signifies the shift from transcription initiation to transcription elongation, where RNA polymerase II synthesizes pre-mRNA in the 5' to 3' direction.