BIO130H1 Lecture Notes - Lecture 10: C-Terminus, Rna Polymerase Ii, Transcription Factor Ii A
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BIO130H1 Full Course Notes
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Bio130 lecture 10: transcription part ii: coli promoters. Dna template: t, rna polymerase puts in a. +1 point: first base going to be transcribed. Everything 5" of that on template strand is called downstream. Promoter sequences located upstream, tend to be two major ones for bacteria: aactgt located 35 bases upstream of +1 site. Not identical in all organisms, similar: tataat: located -10 bases (pribnow box) How these were discovered: promoter sequences quite variable in organisms. Take all upstream sequences for hundreds of organisms, try to line them up (msa) looking for similarities. Sequences always around -35 and -10 points that look very much like these ones (consensus sequences) Most common versions of those sequences, highly conserved across organisms. Specificity of sigma factor: different sigma factors can recognize different promoter sequences. One sigma factor that transcribes one type of set of genes, another that helps with initiation of transcription for other sets of genes.
