Human TFIIH Core Subunit Genes, GTF2H1, GTF2H2, GTF2H3, GTF2H4, ERCC2, and ERCC3, encode six subunits of the nuclear core-TFIIH basal transcription factor. These subunits are involved in transcription-coupled DNA nucleotide excision repair, and basal RNA polymerase II transcription when complexed to CAK (CDK7/Cyclin H/MAT1). Phosphorylated 548-aa 62-kDa GTF2H1 contains 2 BSD domains. The 395-aa 44-kDa GTF2H2 contains a C4-type zinc finger and a VWFA domain. The N-terminus interacts with and regulates XPD, while the C-terminus promotes escape of RNAPII from the promoter. GTF2H2 also interacts with XPB, p62, and p34. Containing a C4-type zinc finger, 303-aa 34-kDa GTF2H3 anchors XPB. ATP-dependent 760-aa 87-kDa ERCC2 DNA helicase anchors CAK to core-TFIIH; interaction with p44 stimulates helicase activity. ERCC3 is a 782-aa 89-kDa ATP-dependent DNA helicase. (NCI) [ ]