General Transcription Factor IIH, Polypeptide 5 (GTF2H5)

General Transcription Factor IIH,Polypeptide 5 is a subunit of transcription/repair factor TFIIH, which functions in gene transcription and DNA repair. This protein stimulates ERCC3/XPB ATPase activity to trigger DNA opening during DNA repair, and is implicated in regulating cellular levels of TFIIH. Mutations in this gene result in trichothiodystrophy, complementation group A.

This protein, called TFB5, is a core component of yeast general transcription and DNA repair factor IIH (TFIIH). Database screening identified a human homolog of 71 amino acids that shares 28% identity with the yeast protein. Giglia-Mari et al. (2004) cloned the human cDNA corresponding to the TFB5 gene from primary fibroblasts.