Introduction The Transcription Complex Basic Cis-acting Sequences Enhancers and Silencers Methylation Trans-acting Factors Signaling Control of Transcription Hormonal Control of Gene Expression Signal Transduction Pathways Study Questions Control of Gene Expression in Eukaryotes WWW Links Genetic Topics

The Transcription Complex RNA polymerase II (the polymerase that transcribes eukaryotic mRNAs) cannot bind to a promoter by itself. Rather, it requires other protein factors that are added in a specific order to the promoter and interact with RNA polymerase II to efficiently transcribe the mRNA. An important question to be resolved is whether trans-acting factors must bind to the promoter before this complex is built. The following table describes features of the transcription factors (TF). Factor and Order Binding Features 1. TFIID binds to the sequence TATA; this sequence is present in all eukaryotic genes and is called the TATA box; TFIID is composed of the TATA box-binding protein (TAP) and more than eight other subunits 2. TFIIA stabilizes the binding of TFIID; prevents inhibitor from disrupting the TFIID complex 3. TFIIB 4. TFIIF- RNA Polymerase II Complex 5. TFIIE, TFIIH, TFIIJ these factors must be added in this order for transcription to occur Copyright © 1997. Phillip McClean