Mnemonic - RNA pol II holoenzyme (my ref)

There are total of six general transcription factors (complexes):

TFIIA (Assist) TFIID to (Dock) to DNA. TFIIB (Binds) to TFIID to recruit RNA pol II. TFIIF (Fidelity) bound to RNA pol II prevents unspecific docking. TFIIE (Elongation) and TFIIH (Helicase) are recruited to docked RNA pol II and prepare from initiation to elongation phase.