Lecture 11 Trxn in Organelles

Lecture 11 Trxn in Organelles - T RANSCRIPTION IN O...

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TRANSCRIPTION IN ORGANELLES 1 Sunday, October 2, 2011
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LAST TIME Regulated transcription during sporulation in B. subtilis Heat shock response in E. coli Acclimation to high light in cyanobacteria Circadian regulation of global transcription in cyanobacteria 2 Sunday, October 2, 2011
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TRANSCRIPTION IN ORGANELLES Mitochondria and Chloroplasts Types of RNA polymerases Composition of RNA polymerases Some evolutionary perspectives 3 Sunday, October 2, 2011
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Learning Outcomes 1. Discuss and apply the experimental design illustrating that cyanobacteria is under circadian control (from Lecture 10) 2. Describe the Endosymbiotic Theory and provide evidence based on molecular characteristics of plastids and mitochondria 3. Describe the features of RNAPs in mt and plastids including: enzymology (features of RNAP subunits) and evolution (current thinking on how the RNAPs evolved). 4. Provide a hypothesis as to why plastids have two functional RNAPs. By the end of this lecture, you should be able to: 4 Sunday, October 2, 2011
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CIRCADIAN RHYTHMS Oscillate with a period of ~24 hours Phase determined by light-dark cycle Once entrained, continue in “constant conditions” http://www.eb.tuebingen.mpg.de/research-groups/nick-foulkes/fish.jpg 5 Sunday, October 2, 2011
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A Circadian System (aka Gene expression!) 6 Sunday, October 2, 2011
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Do circadian clocks exist in bacteria? What tools can we use to figure this out? 7 Sunday, October 2, 2011
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Q1: Are single celled organisms capable of circadian rhythms? A: Yes, we know that single celled organisms bioluminescence according to circadian rhythms. This dinoFagellate Fuoresces at night. Gonyaulax polyedra Source: Physiologia Plantarum (1996) 96 (4):727-732 8 Sunday, October 2, 2011
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Vibrio harveyi Q2: Can bacteria cells bioluminesce? A: Yes, this gram negative bacteria will fuoresce in response to quorum sensing by expressing the luxAB operon, Forming protein called luciFerase ‘milky seas eFFect’ 9 Sunday, October 2, 2011
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Experimental Question: Do bacteria cells have a circadian clock? PpsbAI - promoter for psbAI gene (a p’syn gene) luxA + luxB = Vibrio luciferase gene Method: Engineer bioluminescence in Cyanobacteria by using luciferase genes from Vibrio. Bioluminescence becomes a way to detect circadian rhythms if they exist. 10 Sunday, October 2, 2011
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Hours in continuous light Detection of lux driven by photosynthesis gene promoter 11 Sunday, October 2, 2011
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As time glows by in bacteria Carl Hirschie Johnson Populations of cells can exhibit remarkably precise and stable circadian oscillations. But can single cells achieve such precision in the absence of intercellular communication? For cyanobacteria, it seems so.
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This note was uploaded on 03/29/2012 for the course BIO 359K taught by Professor Mcclelland during the Spring '08 term at University of Texas at Austin.

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Lecture 11 Trxn in Organelles - T RANSCRIPTION IN O...

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