RNA polymerase II general transcription initiation factor activity

Definition

Target type: molecularfunction

A general transcription initiation factor activity that contributes to transcription start site selection and transcription initiation of genes transcribed by RNA polymerase II. The general transcription factors for RNA polymerase II include TFIIB, TFIID, TFIIE, TFIIF, TFIIH and TATA-binding protein (TBP). In most species, RNA polymerase II transcribes all messenger RNAs (mRNAs), most untranslated regulatory RNAs, the majority of the snoRNAs, four of the five snRNAs (U1, U2, U4, and U5), and other small noncoding RNAs. For some small RNAs there is variability between species as to whether it is transcribed by RNA polymerase II or RNA polymerase III. However there are also rare exceptions, such as Trypanosoma brucei, where RNA polymerase I transcribes certain mRNAs in addition to its normal role in rRNA transcription. [GOC:txnOH-2018, PMID:10384286, PMID:10747032, PMID:23442138, PMID:25693126]

RNA polymerase II general transcription initiation factor activity is a crucial step in gene expression, involving the assembly of the pre-initiation complex (PIC) at the promoter region of a gene. This complex comprises RNA polymerase II (RNAPII), a core enzyme responsible for transcribing DNA into RNA, along with several general transcription factors (GTFs): TFIIA, TFIIB, TFIID, TFIIE, and TFIIF. The GTFs act as molecular chaperones, facilitating the recruitment and positioning of RNAPII onto the promoter.

The process begins with the binding of TFIID, which contains the TATA-binding protein (TBP) that specifically recognizes and binds to the TATA box, a DNA sequence motif commonly found upstream of eukaryotic genes. TFIID's binding triggers the recruitment of TFIIA, which stabilizes TFIID's interaction with the promoter. Following TFIIA, TFIIB binds to TFIID, providing a platform for RNAPII to associate with the promoter.

TFIIF, which binds to RNAPII, guides the enzyme to the promoter, ensuring that RNAPII is properly positioned for initiation. Finally, TFIIE joins the complex, playing a role in the recruitment of TFIIH, a crucial factor for unwinding the DNA helix and phosphorylating the C-terminal domain (CTD) of RNAPII.

The phosphorylation of the CTD by TFIIH signals the transition from initiation to elongation, enabling RNAPII to move along the DNA template and transcribe the gene. This elaborate process ensures precise regulation of gene expression, allowing cells to control the production of specific proteins in response to various internal and external signals.'
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Proteins (3)

Compounds (50)