need a job??? david threadgill’s lab is looking for a work-study student… responsibilities...
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Need a Job???
David Threadgill’s Lab is looking for a work-study student…
Responsibilities include general lab maintenance (app. 10 to 20 hours a week)
Perks include an AWESOME working environment with a lot of cool people and interesting research!
Call David Threadgill at 843-6472 for more info
Visit our website at http://152.19.39.101/
Genetic Engineering
of Plants & Animals
Genetic Engineering: Changing the genetic make-up of an organism using biotechnological methods
GE: Genetically Engineered Foods
GM: Genetically Modified Foods
GMO: Genetically Modified Organisms
Transgenic Crops
• Make crops, livestock, etc. more profitable
-- Pest resistance, herbicide resistance, shortened growth period, traits preferred by consumer
• Make medically important substances easy to obtain -- Enzymes, proteins, tissues
• Make transgenic animals for medical and biological research
-- Disease models, gene function studies
Common Applications of GE
Examples of GE crops
• Starlink and Bt Corn: Resistant to common pests
• Tomatoes: “Flavr- Savr” Slow softening ripe tomatoes
• Herbicide resistant soybeans and cotton: “Round-up” Ready
• Tear-free onions (development in progress)
How do you make a GE crop?
• Identify gene that encodes trait of interest
• Transfer DNA into plant cells via bacteria or a gene gun.
• The DNA integrates into the plant’s chromosomes
• Culture the modified plant cells to grow many cells with the desired trait
• Grow the plant cells in a special culture that causes the cells to differentiate
• The plantlets are transferred from the laboratory culture to soil
Cold tolerance
Cold tolerance
Delivery and Integration
Culture and Differentiate
http://www.agwest.sk.ca/sabic_index_tp.shtml
Bt and Starlink Corn
Different forms of the toxin (Cry proteins) can be used to target specific pests
Can be up to 99% effective
Insects can develop resistance
Starlink corn scare
Bacillus thuringiensis (Bt): Soil bacterium that produces a toxin targeting the gut of common pests of corn, such as the European corn borer
Flavr-Savr Tomatoes: Antisense Technology
The PG gene was identified in the tomato and inserted into a plasmid in such a way that a PG antisense transcript is produced
The antisense transcript binds the PG sense mRNA blocking access of the translational machinary eliminating 99% of the PG product
Polygalacturonase (PG): an enzyme expressed during ripening causing depolymerization of the pectin fraction of the cell wall, which results in softening of ripe tomatoes.
Coding
Noncoding
PGGP
GP
Add CMV promoter
Delivery and Integration
Antisense suppression of PG
Isolate DNA
GE Animals
Quick growing Salmon
Healthier Pork
Allergy-proof Cats
“Super Salmon”
A growth hormone in Salmon is normally produced only in warm temperatures
An antifreeze protein was discovered in flounder that is expressed only in cold temperatures
The control elements from the flounder gene were placed upstream of a copy of the salmon growth hormone gene
The salmon with the transgene grow during the warm and cold seasons
Healthier Pork
FAD2 is found in spinach and converts saturated fats into linoleic acid (an unsaturated fat)
The gene was placed in a pig’s genome
The transgenic pigs contain 20 percent less saturated fat
This is the first time a planet gene has been inserted into an animal genome
Cat allergies are thought to be caused by a single protein in the cat’s skin and saliva.
An allergen-free cat could be available by the year 2003, costing somewhere in the region of $1000
The researchers aim to take cat cells and knock out the gene that produces the problem protein, replacing it with an inactive version.
The cell’s nucleus will then be put into a cat egg cell, that has had its own genes removed, creating an embryo that can be implanted into a surrogate mother.
Allergy Proof Cats
Making Medicine though Genetic Engineering
Turning animals (and plants) into pharmaceutical factories
Goat’s Milk
Anti-cancer tomatoes
Pigs for organ harvest
Malaria Free Mosquitoes
Goat milk drug production
Insert gene for antithrombin III (anti-coagulate) into goat genome with necessary signals for secretion into milk
Purify protein from goat’s milk
Drug prevents blood clotting in patients with antithrombin deficiency (homozygous recessive)
Cancer Preventative Tomatoes
Lycopene is a carotenoid that gives tomatoes their red color
It is an antioxidant; carotenoids capture electrically charged oxygen molecules that can damage tissue
People that eat lots of fruits and vegetables containing lycopene have less breast and prostate cancers
A yeast gene is expressed in the tomato that stabilizes the lycopene and results in 3X the amount of lycopene
Pigs for Organ Harvesting
• Xenotransplantation is limited by immune response of recipient
• The rejection response occurs when human antibodies attach to sugar molecules on the surface of the transplanted pig organ's cells, killing the cells
• The gene that produces this sugar molecule, called a-1,3-galactosyltransferase (GGTA1) has been eliminated in a line of miniature swine
• The swine also have organs approximately the same size as human organs
Malaria-Free Mosquitoes
Malaria is a deadly parasite transmitted to humans via mosquitoes
SM1 gene: prevents malaria from entering salivary gland from mosquito gut
SM1 was placed under control of a promoter controlled by feeding in the mosquito genome
Mosquitoes with SM1 were unable to transmit malaria to mice
To effectively eliminate transmission transgenic mosquitoes must be able to survive as well or better than wildtype mosquitoes
Are GE products safe?
Usually involve random insertion into genome
Includes promoters (CaMV) and enhancers that can influence activity of nearby native genes (may activate normally unactive genes such as toxins)
Gene inserted is usually for a foreign protein that could have undesirable effects in addition to the desired effects
Many of the proteins have not previously been eaten in food -- how will consumer be affected?
Fusion proteins / protein folding
Environmental Issues
Cross pollination / breeding with wild species
Production of “super weeds”
Impact on other species (such as the monarch)
• The US and Canada produce 82% of the world’s GM food.
• In 1999 almost one-quarter of our nation's food and fiber crops were genetically engineered
• US GE Crops: 57% of U.S. soybeans, 38% of U.S. corn, 65% of U.S. cotton, 4% of U.S. potatoes, and over 50% of the U.S. and Canadian canola crop• 60% of processed foods sold in grocery stores contain at least a trace of GM ingredients
Have you eaten GM Food?
What do people think about GE?
US, China, and Canada: ~75% of consumers approve
Europe and Japan: Less accepting of GM food (less than 20% approve)
But…knowledge about GE is lacking in the general public
European Survey: Would you buy GM food?
Animals for ResearchTransgenic Mice, Plants, Flies, etc.
Transgenic animals can be created to study gene function and/or human disease genes
Can make a variety of changes to yield information-- Null alleles (insert an antibiotic resistance gene in exon)-- Point mutations -- Deletion mutations (eliminate part of a gene or protein)-- Duplications-- Hypomorphic mutation – changes level of gene expression-- Controlled expression of gene in different spatial or temporal
context
ES cell from brown mouse
Construct to Disrupt Gene of Interest (GOI)
NEO
Transform and select
NEO
GOI
Let ES cells divide
Inject into blastocyst from white mouse and implant in pseudopregnant female
Look for chimeric progeny
Test chimeras for germ-line transmittance
of brown genome
Links of interest...
Trangenic Pets: http://www.transgenicpets.com/
News Collections: http://www.newscientist.com/hottopics/gm/
http://www.agbiotechnet.com/topics/Database/index.asp
http://greennature.com/article299.html
Overview: http://members.tripod.com/c_rader0/gemod.htm
Labeling GM foods: http://www.thecampaign.org/
Pros and Cons: http://scope.educ.washington.edu/gmfood/
Activist Page: http://archive.greenpeace.org/~geneng/