DNA-dependent RNA polymerase II (EC 2.7.7.6) is a complex multisubunit enzyme. It is responsible for the transcription of protein-coding genes.
It is composed of 10 to 14 subunits ranging in size from 220 to 10 kD (POLR2s).
The DNA-dependent RNA polymerase II complex interacts with the promoter regions of genes as well as with a variety of elements and transcription factors to determine essentially all of the parameters that govern transcription, e.g., tissue and development specificity, stress response, etc.
A fraction of the large subunit of Pol II (Pol II LS) is ubiquitinated after exposing cells to UV radiation or cisplatin.
Regulation
Transcription factor IID (TFIID) is a DNA-binding protein complex required for RNA polymerase II (POLR2A) (MIM.180660)-mediated transcription of many, if not all, protein-encoding genes in eukaryotic cells. Other general transcription factors are TFIIA (MIM.600519, MIM.600520), TFIIB (MIM.189963), TFIIE (MIM.189962, MIM.189964), TFIIF (MIM.189968), TFIIG/J, and TFIIH (MIM.189972).
TFIID plays a key role in initiation, since it binds to the TATA element to form a complex that nucleates the assembly of the other components into a preinitiation complex and that may be stable through multiple rounds of transcription.
TAF1, or TAFII250, is the largest subunit of TFIID. Other protein subunits of TFIID include TATA box-binding protein (TBP) (MIM.600075) and numerous other TBP-associated factors (TAFs).
TFIID is thought to interact with TFIIA, which may stabilize its binding, and with TFIIB, which is the next factor to enter the complex.
See also
- germline mutations of TAF1 in X-linked dystonia-parkinsonism (DYT3) (MIM.314250)