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By Lynn More - Olympian High School along with UCSD Protein Transformation Lab Intro UCSD: BioBridge Program E. coli
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What is protein transformation? 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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Fluorescent Proteins-Applications Zebra Fish Transgenic Zebra Fish Neuron Transgenic Mice
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Aequorea victoria and Discovery of GFP- 1960’s OSAMU SHIMOMURA Co-winner of Nobel Prize 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 blue to cyan.
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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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Central Dogma Central Dogma http://www.dnai.org/a/index.html DNA--->mRNA--->Protein--->Trait
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What is a plasmid? What : A small circular piece of DNA naturally occurring in bacteria Origin Amp R GFP Stop promoter PM1 Green Blue Grape PM2 Cherry Tangerine Banana PM means Plasmid Mix Gene of Interest: AMP R - Ampicillin Resistance Antibiotic Resistance Gene of Interest: Fluorescent Protein Why : Can be altered in lab to express protein of interest.
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What is Transformation? Uptake of foreign DNA, often a circular plasmid Bacteria now express cloned fluorescent protein (transcription of gene and translation of mRNA to protein at ribosomes). Bacterial chromosome Plasmid Bacterial chromosome Allow bacteria to grow for 1-3 days on plate with ampicillin. Plasmid
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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 Insert the DNA (plasmid) Using a Heat Shock Method Collect culture DNA Purification X 10 6
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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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Make two Plasmids Pick a Fluorescent Protein gene to insert mCherry mTangerine mBanana GFP Green Fluorescent Protein BFP Blue Fluorescent Protein mGrapemPlum Insulin gene Save a diabetic Factor VIII gene Save a hemophiliac Pest Resistance gene Save a plant Oil Spill gene Save an environmen t Use DNA Ligase (tape or glue) to bond the gene of interest Pick a gene of interest to add to the second plasmid you make Amp R gene Ampicillin resistance Tetra R gene Tetracycline resistance Kan R gene Kanamycin resistance Pen R gene Penicillin resistance Add an antibiotic resistance gene to both plasmids you make. Glue/Tape Tuck Under & Glue/Tape Glue/Tape Tuck Under & Glue/Tape Time to make the second Plasmid Model Congratulations scientists you have just made recombinant DNA: genetically engineered DNA with genes that can save lives! Restriction Enzyme Use DNA Ligase (tape or glue) to bond the gene of interest Restriction Enzyme
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Make a Plasmid Activity #18 1. Cut the DNA with a _______________ (Scissors) 2. My gene of interest was (FP - ________ & __________) 3. My goal is to (FP) - track ____________; save ________ 4. The petri dish would have: ___________ antibiotic; ___________ antibiotic so…I need to make the transformed bacteria resistant to that antibiotic (_____); (_____) 5. What I have made are 2 small circular pieces of DNA with two genes of interest each & they called plasmids.
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Escherichia coli What? AKA (also known as) E. coli Prokaryote Single-celled organism No nucleus No membrane –bound organelles Why? Small, so only need… Food (LB Agar) Little space Warm temps (37˚C) Little humidity Reproduces fast Binary fission x 10 6 Can uptake foreign DNA Clones itself & its contents
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Why calcium chloride? O CH 2 O PO O O Base CH 2 O P O O O Base OH Sugar O Ca ++ Calcium Chloride (CaCl 2 ) Transformation solution CaCl 2 is necessary because: The positive charge of Ca ++ ions neutralizes DNA’s slightly negative charge increases the diffusion of its foreign genetic information through the cell wall and cell membrane into the bacteria.
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The what’s and why’s of Heat Shock Incubate on ice (10 minutes) slows fluid cell membrane (constricts pore size) Heat-shock (42˚C for 45 seconds) increases permeability of membranes (dilates/opens pores, allowing the plasmid to get inside the bacteria) Incubate on ice (2 minutes) slows fluid cell membrane (reduces permeability again, “locking” the plasmid inside the bacteria)
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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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More Review??
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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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How are plasmids engineered? DNA Plasmid Vector Cut plasmids open with restriction enzymes Cut genomic DNA into fragments + Ligate (paste) fragments into cut DNA vector End result: Plasmid containing FP gene Host DNA fragments (i.e. coral or jellyfish FP coding DNA)
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The plasmids we have… The plasmid serves as a carrier or transporter of a genetically engineered DNA segment into a host cell. EcoRI (pronounced "eco R one") is a commonly used restriction enzymerestriction enzyme isolated from certain strains of E. coli used to cut DNA at specific locations.E. coli Gene for antibiotic resistance Restriction Enzyme Area of Interest - Fluorescent Protein Restriction Enzyme Cuts the DNA Foreign DNA Recombinant DNA DNA Ligase Sticky ends help attach to the plasmid
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Human cell stained with two different fluorescent proteins to visulalize cytoskeletal components. Transfected with GFP-tubulin / mCherry actin (Ben Giepmans) Cellular organelles “marked” with FPs C Elegans transfected with GFP tubulin construct (Susan Kline)
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Transcription / Translation Campbell
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