Ways to Regulate Transcription Alternate sigma factor usage

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Ways to Regulate Transcription Alternate sigma factor usage: controls selective transcription of entire sets

Ways to Regulate Transcription Alternate sigma factor usage: controls selective transcription of entire sets of genes vegetative (principal s) s 70 צמיחה heat shock nitrogen starvation (16 -19 bp) TTGACA s 32 s 60 +1 TATAAT (5 -9 bp) A +1 CNCTTGA (13 -15 bp) CCCATNT (5 -9 bp) A CTGGNA (6 bp) TTGCA +1 (5 -9 bp) A !19. 6. 2008 – התרגיל ביום חמישי זה

Pre-m. RNA * micro. RNAs (mi. RNA) RNA molecules of about 21– 23 nucleotides

Pre-m. RNA * micro. RNAs (mi. RNA) RNA molecules of about 21– 23 nucleotides in length, which regulate gene expression. are processed from primary transcripts known as pri-mi. RNA.

5’UTR 3’UTR

5’UTR 3’UTR

RNA polymerase

RNA polymerase

שלבי הטרנסקריפציה Initiation • Elongation • Termination •

שלבי הטרנסקריפציה Initiation • Elongation • Termination •

Stages in Initiation of Transcription • Bacterial transcription • Closed complex: holoenzyme+promoter • Open

Stages in Initiation of Transcription • Bacterial transcription • Closed complex: holoenzyme+promoter • Open complex (DNA melting, not need ATP) • Abortive transcripton • Productive initiation – Transcribe past +9 – Sigma dissociates • Elongation • Eukaryotic transcription • Preinitiation complex (PIC) assembly • PIC activation (DNA melting, needs ATP) • Abortive transcription • Productive initiation – CTD phosphorylated – Promoter clearance • Elongation

initiation

initiation

Elongation NTPs

Elongation NTPs

TERMINATION • RNA polymerase meets the terminator • Terminator sequence: AAUAAA • RNA polymerase

TERMINATION • RNA polymerase meets the terminator • Terminator sequence: AAUAAA • RNA polymerase releases from DNA • Prokaryotes-releases at termination signal • Eukaryotes-releases 10 -35 base pairs after termination signal

transcription

transcription

Transcription regulation

Transcription regulation

Gene expression

Gene expression

Basics of cell biology: development Fertilized egg

Basics of cell biology: development Fertilized egg

Basics of cell biology: development Cells differentiation is due to different gene Switches going

Basics of cell biology: development Cells differentiation is due to different gene Switches going on and off These cells are different because they express a subset of their 24, 000 genes

Promoter Gene To specify a new cell: place it in the right environment or

Promoter Gene To specify a new cell: place it in the right environment or

EGF Hedgehog Wnt Promoter Gene Retinoic acid FGF HGF To specify a new cell:

EGF Hedgehog Wnt Promoter Gene Retinoic acid FGF HGF To specify a new cell: place it in the right environment or Substitute drugs/proteins for environment Mophogens

Chromosome localization in interphase In interphase, chromosomes appear to be localized to a sub-region

Chromosome localization in interphase In interphase, chromosomes appear to be localized to a sub-region of the nucleus.