Transcription initiated by RNA polymerase II and purified transcription factors from liver. A complex set of promoter sequences governs formation of the initial complex.

Using a transcription system derived from rat liver, we have investigated the function of the TATA-box and cap site/initiator regions in assembly of stable intermediates on the pathway leading to formation of a functional RNA polymerase II preinitiation complex. Our findings argue that neither the TATA-box region nor the cap site/initiator region functions independently in the binding of transcription factors during formation of these intermediates, but, rather, the two sequence elements function cooperatively to direct assembly of a stable preinitiation complex at the promoter.