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TATA

TATA. INR. RE. TATA. INR. Transcription. Response elements (REs) function in gene regulation. Activator protein requires an inducer to bind to the response element. REs bind transcription factor proteins that are activated

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TATA

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  1. TATA INR RE TATA INR Transcription Response elements (REs) function in gene regulation. Activator protein requires an inducer to bind to the response element.

  2. REs bind transcription factor proteins that are activated by external signals e. g. steroid hormones, phorbol esters, heat-shock. Inducer RE Activator protein Heat-shock HSE CNNGAANNTCCNNG HSTF Glucocorticoid GRE TGGTACAAATGTTCT Receptor Phorbol ester TRE TGACTCA AP1 Serum SRE CCATATTAGG SRF

  3. Enhancer UEs REs Promoter UE TATA INR Enhancers - DNA sequences that strongly increasetranscription. • ~ 100 to 200bp of DNA composed of upstream and • response elements. - can be several kb away from the target gene, upstream or downstream.

  4. Activator proteins bound to elements in downstream enhancer D A Pol II B TATA INR DNA looping brings enhancer close to promoter.

  5. Pol II promoters contain a patchwork arrangement of elements. e. g. metallothionein promoter GRE BLE MRE MRE BLE TRE MRE GC MRE TATA start -250 -200 -100 -25 MRE metal response elements BLE basal level elements GRE glucocorticoid response element

  6. -180 -107 -45 +20 Core promoter UCE UBF1 SL1 RNA pol I promoters Pol I only transcribes rRNA precursors from a single type of promoter. The pol I promoter consists of 2 elements: the UCE and the core promoter.

  7. Outer surface of TBP interacts with a subunit of RNA pol I. TBP The core promoter and the UCE are GC rich and 85% identical. Transcription factors UBF1 and SL1 bind the UCE and core elements and assist binding of RNA Pol I at the start point. One of the 4 subunits of SL1 is TBP. In this case TBP does not bind promoter DNA directly but interacts with Pol Iduring assembly of the initiation complex.

  8. Start point +55 +80 5S rRNA promoter Pol III promoters can be upstream or downstream of the start-point. Promoters for snRNAs are upstream. Promoters for 5S rRNA and tRNA are downstream.

  9. Start point Box A Box B TFIIIC TFIIIC TFIIIB TFIIIC TFIIIC TFIIIB Pol III RNA pol III type 2 internal promoters Downstream elements bind TFIIIC. TFIIIB recruits Pol III TFIIIC positions TFIIIB at the start point.

  10. Start point Box A Box C TFIIIB TFIIIB TFIIIA TFIIIC TFIIIC TFIIIC Pol III RNA pol III type 1 internal promoters Downstream elements initially bind TFIIIA and TFIIIC. TFIIIB eventually recruits Pol III at the start point.

  11. TBP TFIII B also includes TBP. Within TFIIIB, TBP interacts with RNA pol III but does not bind a specific DNA sequence within the promoter. The convex surface of TBP can probably interact with a subunit that is common to all 3 RNA polymerases.

  12. OCT PSE TATA start UEs Pol III transcribes some genes (for snRNAs) from upstream promoters. These are similar to Pol II promoters. They have TATA boxes and 2 upstream elements, OCT and PSE. The TATA box is recognised by a factor that includes TBP.

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