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Fluorescent Protein BACTERIAL TRANSFORMATION
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What is genetic transformation…and why do it? Introducing DNA that expresses preferred gene(s) into a host to: 1. Inhibit or silence the expression of a gene 2. Carry out certain functions 3. Used as markers to track the location and function of the gene i.e. - allows you to determine its function or importance i.e. - make insulin, clot blood, resist pests, resist antibiotics, eat oil i.e. - fluorescent proteins
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Bioluminescent organism produces its own light. A fluorescent organism absorbs light at one wavelength (UV) and a re- emits the light at a visible wavelength= color Scorpion- UV Light Scorpion- Natural Light http://fireflyforest.net/firefly/2006/11/13/fluorescent-scorpion-in-uv-light/ Natural Light In the Dark BioluminescenceFluorescence Bioluminescence vs. Fluorescence
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www.worldnetcams.com/sealife/cerianthus.jpg Many organisms have the ability to fluoresce Many organisms have the ability to fluoresce Jellyfish Amphipod Spider’s palps Mushroom Sea Anemone Coral
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Jellyfish- Bioluminescence and Fluorescene
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Aequorea victoria and Discovery of GFP- 1960’s OSAMU SHIMOMURA Co-winner of Nobel Prize
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Fluorescent Proteins-Applications Fish Transgenic Fish Neuron Transgenic Mice
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xxx GFP-chromatin met ana pro telo GFP-membrane cyto met ana telo GFP-tubulin met ana pro telo Visualizing FPs in Live Worms ……analyzing mitosis from 3 perspectives:
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xxx MITOSIS a similar process in diverse species ……...using various organisms to understand humans: Frog Egg Extract + sperm DNA A. Desai Frog Cell C.E. Walczak Marsupial Cell S.L. Kline Fly Embryo T. Megraw Frog Egg Extract + DNA-coated beads R. Heald Human Cell J. Waters Worm Embryo I.M. Cheeseman
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Green Fluorescent Protein (GFP) is produced by a number of organisms, such as the jellyfish. There are three amino acids which are critical for GFP’s green fluorescent color. Only a 1 amino acid difference changes green to blue, and blue to cyan Only a 1 amino acid difference changes green to blue, and blue to cyan. Aequoria victoria
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Roger Tsien and Rainbow Proteins DsRed.T 1 Dimer 2 mRFP1 mgrape 1 mHoneydew mBanana mOrange mTangerine mStrawberry mCherry 17 Mut 33 Mut 6 Mut 8 Mut 3 Mut 7 Mut 4 Mut 3 Mut
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The rainbow of mFruit Fluorescent Proteins
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E. coli
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Central Dogma Central Dogma http://www.dnai.org/a/index.html DNA--->mRNA--->Protein--->Trait
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What is a plasmid? A small circular piece of DNA Naturally occurring in bacteria & yeast Can be altered in lab to express protein of interest Origin Amp R GFP Stop promoter PM1PM2 GreenCherry BlueTangerine GrapeBanana
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Vector - any agent that acts as a carrier or transporter (ie. a virus or plasmid) that conveys a genetically engineered DNA segment into a host cell. EcoRI (pronounced "eco R one") is a commonly used restriction enzyme isolated from certain strains of E. coli used to cut DNA at specific locations. Gene for antibiotic resistance produces ß-lactamase EcoRI Area of Interest - Fluorescent Protein EcoRI Foreign DNA Recombinant DNA DNA Ligase Sticky ends help attach to the plasmid End result = a plasmid containing the FP gene From GFP: From RFP: PM1PM2 GreenCherry BlueTangerine GrapeBanana How are plasmids engineered? (aka: genes transformed)
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What is Transformation? Plasmid Uptake of foreign DNA, often a circular plasmid Bacterial chromosome
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What is Transformation? Bacterial chromosome Allow bacteria to grow for 1-3 days on plate with ampicillin. Plasmid Uptake of foreign DNA, often a circular plasmid Bacterial chromosome
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What is Transformation? Bacteria now express cloned fluorescent protein… Bacterial chromosome Allow bacteria to grow for 1-3 days on plate with ampicillin. Plasmid Uptake of foreign DNA, often a circular plasmid Bacterial chromosome
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How does the plasmid get in? O CH 2 O PO O O Base CH 2 O P O O O Base OH Sugar O Ca ++ CaCl 2 - Calcium Chloride (Transforming Sol’n) Positive charge of Ca ++ ions shields negative charge of DNA phosphates
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How does the plasmid get in? Incubate on ice = slows fluid cell membrane Heat-shock = increases permeability of membranes, allowing plasmids to get inside bacteria (42˚C for 45 Seconds) Leave in heat 45 seconds! Too short, and bacteria won't let in plasmid. Too long, and the bacteria will die. Incubate immediately on ice = slows fluid cell membrane again, “locking the plasmids inside.”
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Antibiotic Resistance Ampicillin - is an antibiotic. Kills any normal bacteria. The regular bacteria would compete for food and space. We want the antibiotic to eliminate them. Origin Amp R GFP Stop promoter Amp R - the gene for Ampicillin Resistance This gene makes a protein (enzyme) that breaks down the ampicillin and makes it edible for the transformed bacteria
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Why Ampicillin? Ampicillin inhibits cell growth. Only cells that can inactivate the ampicillin around them will grow. Ampicillin resistance is tied to (expressed with) the fluorescent protein gene Ampicillin is a selection mechanism that only allows transformed bacteria to grow on the plate
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What’s happening in the petri dish? Ampicillin acts as a __________________ that only allows ___________ bacteria to _____ on the plate Represent ___________________________________________Ampicillin - an antibiotic that inhibits bacterial growth Represent ______________Bacteria growth Represents _________________________________________ LB Agar - a nutrient substrate to encourage growth Represent _________________________________ Genetically transformed bacteria that are: 1. Resistant (or shielded) from the effects of ampicillin 2. Marked with a Fluorescent Protein selection mechanism transformedgrow ______________________Bacteria killed by ampicillin
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Plasmid = a vector that carries genetically engineered DNA segment into a host cell. Recombinant DNA Bacteria cell Bacterial chromosome Bacteria plated on LB agar + antibiotic Only bacteria containing Recombinant DNA grow cloning DNA (plasmid) insertion Using a Heat Shock Method Collect culture DNA Purification Why is that? Why use bacteria? Do the two genes do?
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Go to: Protein Transformation Lab Preview.ppt UCSD: BioBridge Program
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Students make bags in groups of four: 2 empty microcentrifuge tubes 4 disposable transfer pipette Inoculating loops OR sterile tips 2 cotton swabs Teacher will have at lab tables for each group of four: 1 waterproof pen - for labeling 1 LB plate 2 LB/AMP plates 1 microcentrifuge tube of CaCl2 on ice Ice bucket (cup with ice and water) 1 tube of plasmid labeled either PM1 or PM2 on ice. 2 Lab station waste containers - one with 10% bleach, other empty Tape for sealing plates after inoculation FP Transformation materials checklist
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FP transformation procedure + LB/Amp + - LB/Amp - Control - Colonies of bacteria With plasmids Testing effectiveness Of Ampicillin “Lawn” testing viability of the bacteria CaCl 2 + Bacteria + Plasmid (PM1 or PM2) CaCl 2 + Bacteria + Control (TE or dH 2 O) Purpose of Each plate
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FP transformation procedure
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DNA Transformation by BioBridge Online resources: http://biobridge.ucsd.edu/ http://biobridge.ucsd.edu/
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