gene regulation: prokaryotes - wou homepageguralnl/311progenereg.pdf · 2006. 10. 31. · gene...
TRANSCRIPT
![Page 1: Gene Regulation: Prokaryotes - WOU Homepageguralnl/311progeneReg.pdf · 2006. 10. 31. · Gene Regulation: Prokaryotes Author: Western Oregon University Created Date: 10/31/2006 3:06:39](https://reader035.vdocument.in/reader035/viewer/2022070108/6041d8f7653c1837531382d7/html5/thumbnails/1.jpg)
Gene Regulation: Prokaryotes• Introduction• Why gene regulation?• Lac Operon• Structure of the
operon • Operation of the
operon • Positive regulation • Trp Operon
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Why gene regulation?
• Constitutive genes • Facultative genes • Jacob & Monod • Example: Lac operon• B-galactosidase
cleaves lactose
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Jacob and Monod expt
• Is enzyme made de novo or inactive in cytosol?
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Lac Operon:Structure of the operon
• Operon: cluster of genes for a particular function
• Polycistronic • Three structural genes
(B-galactosidase, permease, transacetylase)
• Operator • Promoter
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Lac operon
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Operation of the operon
• repressor protein • inducer molecule
(allolactose)
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Mutations
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Mutations
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Studies of regulation
• Partial diploids (merozygotes)
• cis and trans factors • Oc mutants • i gene mutants: Is
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Studies of regulation
• cis and trans regulation
• Oc mutants
• I- gene mutants
• P- and Is mutants
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Positive regulationEffect of glucose and lactose CAP/cAMP regulation Diauxic growth
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Trp Operon
• Structural genes (5) • Repressible operon • Co-repressor • Attenuator (unique to
prokaryotes)
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Repressible Gene
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Attenuator
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Attenuator