09BIS1012013TransciptLect9-1

Lrodriguez 2013

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Unformatted text preview: IS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez 22 Consensus Logos and Sequences Logos Eukaryotic Promoter Sequence Making Sequence Logos BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez 23 Transcription Elongation After the RNAP holoenzyme moves 5 to 8 bases away from the After promoter, the σ factor dissociates from the RNAP and the core RNAP completes transcription. Elongation takes place at a rate of about 40 to 60 bases/sec Elongation and pauses occasionally at GC rich regions. The significance of this pausing is not clear. pausing As the RNAP core enzyme transcribes the gene, the helix is As unwound 18 to 30bp and a DNA/RNA hybrid of 12 to 17 bp is formed within this denatured bubble in the DNA. formed BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez 24 EM of E. coli Transcription EM E. The electron The micrograph (EM) at the right shows multiple transcription initiation events. initiation As the mRNAs grow As in length, ribosomes attached to begin protein synthesis (translation). (translation). The length of mRNA The indications the direction of transcription. transcription. Promoter BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez 25 Transcription Termination Transcription There are 3 stages to the termination There stage: (1) cessation of RNA synthesis; (1) (2) release of the newly made RNA and (3) dissociation of the RNAP from the DNA. (3) This can be accomplished...
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This note was uploaded on 02/12/2014 for the course BIS 101 taught by Professor Simonchan during the Spring '08 term at UC Davis.

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