TFIIH
| general transcription factor IIH, polypeptide 1, 62kDa | |
|---|---|
| Identifiers | |
| Symbol | GTF2H1 |
| Alt. symbols | BTF2 |
| Entrez | 2965 |
| HUGO | 4655 |
| OMIM | 189972 |
| RefSeq | NM_005316 |
| UniProt | P32780 |
| Other data | |
| Locus | Chr. 11 p15.1-p14 |
| general transcription factor IIH, polypeptide 2, 44kDa | |
|---|---|
| Identifiers | |
| Symbol | GTF2H2 |
| Alt. symbols | BTF2, TFIIH, BTF2P44, T-BTF2P44 |
| Entrez | 2966 |
| HUGO | 4656 |
| OMIM | 601748 |
| RefSeq | NM_001515 |
| UniProt | Q13888 |
| Other data | |
| Locus | Chr. 5 q12.2-13.3 |
| general transcription factor IIH, polypeptide 3, 34kDa | |
|---|---|
| Identifiers | |
| Symbol | GTF2H3 |
| Alt. symbols | BTF2, TFIIH |
| Entrez | 2967 |
| HUGO | 4657 |
| OMIM | 601750 |
| RefSeq | NM_001516 |
| UniProt | Q13889 |
| Other data | |
| Locus | Chr. 12 q24.31 |
Transcription factor II Human (TFIIH)Transcription Factor II H is an important protein complex, having roles in transcription of various protein-coding genes and DNA nucleotide excision repair pathways. TFIIH first came to light in 1989 when general transcription factor-δ or basic transcription factor 2 was characterized as an indispensable transcription factor in vitro. This factor was also isolated from yeast and finally named as TFIIH in 1992.
TFIIH consists of ten subunits, 7 of which (XPD, XPB, p62, p52, p44, p34 and TTDA) form the core complex. The cyclin activating kinase-subcomplex (CDK7, MAT1, and cyclin H) is linked to the core via the XPD protein Two of the subunits, ERCC2/XPD and ERCC3/XPB, have helicase and ATPase activities and help create the transcription bubble. In a test tube these subunits are only required for transcription if the DNA template is not already denatured or if it is supercoiled.
Two other TFIIH subunits, CDK7 and cyclin H, phosphorylate serine amino acids on the RNA polymerase II C-terminal domain and possibly other proteins involved in the cell cycle. Next to a vital function in transcription initiation, TFIIH is also involved in nucleotide excision repair.
It is responsible for giving the 'go' signal which is why it is assembled last.
TFIIH is a general transcription factor that acts to recruit RNA PolII to the promoters of genes. It functions as a helicase that unwinds DNA. It also unwinds DNA after a DNA lesion has been recognized by either the global genome repair (GGR) pathway or the transcription-coupled repair (TCR) pathway of NER.
Mutation in genes ERCC3/XPB, ERCC2/XPD or TTDA cause trichothiodystrophy, a condition characterized by photosensitivity, ichthyosis, brittle hair and nails, intellectual impairment, decreased fertility and/or short stature.
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