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pGLO ™ & GFP PowerPoint Presentation
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pGLO ™ & GFP

pGLO ™ & GFP

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pGLO ™ & GFP

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  1. pGLO™& GFP

  2. pGLO™ Transformationand Purification of Green Fluorescent Protein (GFP) Instructors Stan Hitomi Coordinator – Math & Science San Ramon Valley Unified School District Danville, CA Kirk Brown Lead Instructor, Edward Teller Education Center Science Dept. Chair, Tracy High School and Delta College, Tracy, CA Sherri Andrews, Ph.D. North Carolina School of the Arts Winston-Salem, NC

  3. WhyTeach Bacterial Transformationand ProteinPurification? • Powerful teaching tool • Meet national science standards • Laboratory extensions • Real-world connections • Link to careers and industry

  4. DNA RNA Protein Trait Central Framework of Molecular Biology

  5. Links to Real-world • GFP is a visual marker • Study of biological processes (example: synthesis of proteins) • Localization and regulation of gene expression • Cell movement • Cell fate during development • Formation of different organs • Screenable marker to identify transgenic organisms

  6. pGLO™ Bacterial Transformation Kit Bio-Rad pGLO Kit Advantages • Standards-based • Comprehensive curricula for inquiry-based investigations • Compatible with 50 minute class periods • Serves entire class of 32 students (up to 4 students per group) • Cost-effective • Success in student’s hands • Safe • Striking results!

  7. Green Fluorescent Protein (GFP) Chromatography Kit GFP Purification kit advantages • Links to real world science • Laboratory extensions • Tangible results • Leverages equipment • Amazing results

  8. Transformation Procedure Day 2 Day 1

  9. GFP Workshop Timeline • Introduction • Transform bacteria with pGLO plasmid • Purify GFP using column chromatography

  10. pGLO Bacterial Transformation Kit

  11. GFP Beta-lactamase Ampicillin Resistance What is Transformation? • Uptake of foreign DNA, often a circular plasmid

  12. What is a plasmid? • A circular piece of autonomously replicating DNA • Originally evolved by bacteria • May express antibiotic resistance gene or be modified to express proteins of interest

  13. The Many Faces of Plasmids Transmission electron micrograph Graphic representation Agarose gel

  14. Protein Size • Beta Lactamase • Ampicillin resistance • Green Fluorescent Protein (GFP) • Aequorea victoria jellyfish gene • araC regulator protein • Regulates GFP transcription

  15. Bacterial Transformation Cell wall GFP Bacterial chromosomal DNA Beta lactamase (ampicillin resistance) pGLO plasmids

  16. Bacterial DNA Bacterial cell Plasmid DNA Genomic DNA

  17. Transcriptional Regulation • Lactose operon • Arabinose operon • pGLO plasmid

  18. ara Operon lac Operon araC B A D LacI Z Y A Effector (Arabinose) Effector(Lactose) araC B A D LacI Z Y A RNA Polymerase RNA Polymerase B A D araC Z Y A Transcriptional Regulation

  19. ara GFP Operon ara Operon araC GFP Gene araC B A D Effector(Arabinose) Effector (Arabinose) araC B A D araC GFP Gene RNA Polymerase RNA Polymerase B A D araC araC GFP Gene Gene Regulation

  20. Methods of Transformation • Electroporation • Electrical shock makes cell membranes permeable to DNA • Calcium Chloride/Heat-Shock • Chemically-competent cells uptake DNA after heat shock

  21. Transformation Procedure • Suspend bacterial colonies in Transformation solution • Add pGLO plasmid DNA • Place tubes in ice • Heat-shock at 42°C and place on ice • Incubate with nutrient broth • Streak plates

  22. Reasons for Performing Each Transformation Step? Ca++ O Ca++ O P O Base • Transformation solution = CaCI2 Positive charge of Ca++ ions shields negative charge of DNA phosphates O O CH2 Sugar O Ca++ O O P Base O O CH2 Sugar OH

  23. Why Perform Each Transformation Step? Cell wall GFP 2. Incubate on ice slows fluid cell membrane 3. Heat-shock Increases permeability of membranes 4. Nutrient broth incubation Allows beta-lactamase expression Beta-lactamase (ampicillin resistance)

  24. What is Nutrient Broth? • Luria-Bertani (LB) broth • Medium that contains nutrients for bacterial growth and gene expression • Carbohydrates • Amino acids • Nucleotides • Salts • Vitamins

  25. LB/Amp LB/Amp/Ara LB Grow?Glow? • Follow protocol • On which plates will colonies grow? • Which colonies will glow?

  26. Volume Measurement

  27. GFP Chromatography Kit

  28. GFP Purification Procedures Day 2 Day 1 Day 3

  29. Why Use Chromatography? • To purify a single recombinant protein of interest from over 4,000 naturally occuring E. coli gene products.

  30. Column Chromatography • Chromatography used for protein purification • Size exclusion • Ion exchange • Hydrophobic interaction

  31. + + + + + - - - - - + + + + + HydrophobicInteractions Aqueous solution = hydrophobic High salt = hydrophobic Hydrophobic bead H O - - + H O O S N H H O O - O S O - O

  32. Hydrophobic Interaction Chromatography:Steps 1–3 • Add bacterial lysate to column matrix in high salt buffer 2. Wash less hydrophobic proteins from column in low salt buffer 3. Elute GFP from column with no salt buffer

  33. Step 1:Hydrophobic Interaction Chromatography • Add bacterial lysate to column matrix in high salt buffer • Hydrophobic proteins interact with column

  34. Step 2:Hydrophobic Interaction Chromatography • Wash less hydrophobic from column with low salt buffer • Less hydrophobic E. coli proteins fall from column • GFP remains bound to the column

  35. Step 3:Hydrophobic Interaction Chromatography • Elute GFP from column by adding no salt buffer GFP • Released from column matrix • Flows through the column

  36. Helpful Hints:Hydrophobic Interaction Chromatography • Add a small piece of paper to collection tube where column seats to insure column flow • Rest pipette tip on side of column to avoid column bed disturbance when adding solutions • Drain until the meniscus is just above the matrix for best separation