Upstream element is octamer which has another octamer

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Unformatted text preview: mmon upstream elements CAAT described, often at around -80 but can function at range of distances from the start site distances β -GLOBIN PROMOTER: MUTAGENESIS REVEALS -GLOBIN UPSTREAM ELEMENTS UPSTREAM GC box GC (-90) CAAT box CAAT (approx -75) (approx TAT A box • GC box is another common promoter element that often GC appears in multiple copies in a promoter, present in either orientation orientation • another common upstream element is octamer, which has another octamer which 8 bp consensus sequence bp TBP & TATA- or TATA-LESS PROMOTERS TBP • TATA-containing TATA-containing promoter: TBP binds promoter TATA box TATA • TATA-less TATA-less promoter: TBP cannot bind but tethered to TAFs bound at Inr bound • TATA-less with TATA-less GC boxes: TBP indirectly tethered by Sp1 bound to GC boxes boxes ELEMENT COMBINATIONS IN PROMOTERS ELEMENT • GC, CAAT, TATA GC, boxes & octamer sites (8bp consensus element) organized “mix & match” in promoters - no one element is common to all promoters all • Importance of Importance elements determined by base substitutions, deletion, linker scanning, and primer extension extension GC-BOXES IN SV40 EARLY PROMOTER STUDIED WITH BASE CHANGES BASE • Sp1 binds GC-boxes - transcription levels Sp1 reduced as no. of intact GC boxes declines reduced UPSTREAM TRANSCRIPTION FACTORS UPSTREAM • Module Consensus DNA DNA • TATA BOX TATAAA ~10bp • CAAT BOX GGCCAATCT ~22bp • GC BOX GGGCGG ~20bp • Octamer ATTTGCAT ~20bp • Octamer ATTTGCAT ~23bp • ΚB GGGACTTTCC ~10bp ~10bp • ATF GTGACGT ~20bp Factor TBP CTF/NF1 SP1 Oct-1 Oct-2 N FΚ B SP1 -Upstream elements are bound by factors that are generally ubiquitous, so Upstream most promoters which contain elements will be bound most -However, some upstream elements bound by several different factors ie. -However, ie CAAT box bound by tissue-specific factors CAAT -Footprinting indicates factors bind more than just consensus DNA-so -Footprinting upstream region could be covered with factors upstream UPSTREAM TRANSCRIPTION FACTORS UPSTREAM -TATA & Inr determine -TATA location of both basal complex assembly & transcript initiation transcript -Upstream elements affect -Upstream frequency of initiation, and therefore gene expression, therefore most likely by acting on the most TFIIs...
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This note was uploaded on 03/26/2014 for the course MBB 321 taught by Professor Davidson during the Spring '11 term at Simon Fraser.

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