Final answer:
The assembly of the TF2D-TBP complex and the binding of additional factors to RNA polymerase II leads to the formation of the transcription initiation complex, which is essential for the initiation of mRNA synthesis.
Step-by-step explanation:
Once the TF2D-TBP complex distorts and other factors bind to polymerase II, a structure known as the transcription initiation complex is formed. This complex includes a series of basal transcription factors designated as TFIIA through TFIIJ, which assemble on the DNA template, enhancing the stability of the complex and facilitating the recruitment of RNA polymerase II.
This assembly process is initiated by the binding of TFIID to the TATA box within the promoter region. Subsequent binding of other factors such as TFIIA and TFIIB, along with TFIIE, TFIIF, and TFIIH, leads to the complete formation of the initiation complex.
After RNA polymerase II joins the complex, it undergoes phosphorylation, which triggers the release of some transcription factors, positioning RNA polymerase II correctly to start synthesizing the mRNA.