BIOC0007 TRANSCRIPTION EXAM QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS VERIFIED

BIOC0007 TRANSCRIPTION EXAM QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS VERIFIED RNA polymerase II Eukaryotic; 12 core subunits, 10 essential RNA polymerase Prokaryote; 5 core subunits: ω- stabilises RNA polymerase complex, α1/α2- scaffolding role/protein interaction, β- catalytic site/rNTPs bind, β'- DNA binding, forms transcription bubble Initiation in prokaryotes RNA polymerase binds promoter sequence, binds sigma factor Sigma factor σ1: prevents premature dissociation of RNA pol. σ2: separates dsDNA, stabilises ssDNA σ3/4: stabilises interactions between σ factor, polymerase, and promoter 3.2 region: loop between σ3 and σ4, positions rNTPs on active site and facilitates RNA pol. promoter escape Eukaryotic core promoter recognition TATA box, INR (initiator element), BRE (TFIIB recognition element), DPE (downstream promotor element), DCE (downstream core element), MTE (motif ten element) Eukaryotic regulatory promoter recognition Modulate gene expression, more distinctly located; enhancers, silencers, insulators Eukaryotic preinitiation complex step by step in vitro 1. TBP binds TATA box, causes distortion 2. TBP-associate factors (TAFs) bind INR and DPE/DCE/MTE 3. TFIIA stabilises TBP-DNA interaction 4. TFIIB binds BRE, positions and pulls Pol. II to TSS