NCIt definition : TFIIH is a multisubunit factor consisting of at least 5 polypeptides of 92, 62, 43,
40, and 35 kD. The nonphosphorylated form of RNA polymerase II is recruited by TFIIF
to the DB complex (a DNA-protein complex composed of the TATA-binding protein subunit
of TFIID in association with the TATA motif and TFIIB). This complex is then recognized
by TFIIE, TFIIH, and TFIIJ to generate a transcription-competent complex. Phosphorylation
of the C-terminal domain of the largest subunit of RNA polymerase II controls the
transition from transcription initiation to elongation. The general transcription
factor TFIIH contains a kinase activity capable of phosphorylating this domain. Factors
that promote the association of RNA polymerase II with the preinitiation complex stimulate
this activity. TFIIE, which is required for the stable association of TFIIH with the
preinitiation complex, affects the processivity of TFIIH kinase. (from OMIM 189972);