The general transcription factor complex Transcription factor II H (TFIIH) core complex, is a subcomplex of the TFIIH holoenzyme required in RNA pol II transcription with an ATP-dependent DNA helicase activity required for promoter DNA opening. TFIIH also functions in nucleotide excision repair (NER). After complex loading and the verification step of NER, the cyclin-dependent protein kinase-activating kinase (CAK) subcomplex dissociates and the TFIIH core complex functions independently. (Adapted from
PMID:25693126,
PMID:21592869 and
PMID:30798933).