- Slides: 36
Definitions: Genetically modified organisms (GMO’s): -Organisms whose genes have been altered using genetic engineering techniques. Transgenic organisms - Most GMO’s are transgenic organisms… they have received genes from a different organism. Ex. A mouse is given a gene from a human. The mouse is a transgenic GMO. Trans- ; across (across species in this case)
How Do They Do It?
GMO’s at home: Zebra danio Glo. Fish 1. Zebra danio was genetically engineered with a gene from sea coral that causes the fish to glow in the presence of environmental toxins. 2. Gene was inserted into the embryo of the fish. 3. First GMO available as a pet.
GMO’s in research: GFP (green fluorescent prote GFP Mice 1. Gene from a jellyfish (Aequorea victoria) that codes for GFP was inserted into the embryos of mice. Aequorea victoria (jellyfish, phylum cnidaria)
GMO’s in research: GFP (green fluorescent protein) – a reporter protein 1. GFP is used in cellular and molecular biology. 2. You can attach this protein to any other protein you want making it a reporter protein. - It “reports” to you where the protein is going since it emits green light (similar to radioactivity in that sense)
GMO’s in research: - GFP has been attached to a protein called MFD, which is found in peroxisomes. - Those little green dots are peroxisomes… - You can track any protein you want…in a single cell or an entire organism
Transgenic Cattle? ? ? Dairy cows carrying extra copies of two types of casein genes produce 13% more milk protein Not only will this make the milk more nutritious, it would allow for less milk to make more cheese Currently the milk from these animals is under FDA review The important difference between this & other transgenics is that the DNA added is not foreign
Transgenic Fish Tilapia Salmon/trout Catfish Can grow up to 6 times faster than wildtype fish Most have extra copies of growth hormone (GH) gene Transgenic Wildtype http: //www. nature. com/nbt/journal/v 19/n 6/images/nbt 0601_500 a_I 1. jp
The transgene used to increase growth utilizes an antifreeze protein promoter connected to the GH c. DNA Antifreeze promoter from pout As water temperature drops the GH gene is turned on The fish continue to grow when normally they would not http: //pubs. acs. org/hotartcl/chemtech/99/jun/fletcher. htm
Concerns if these ‘supersized’ transgenic fish got loose: Transgenic fish are farm-raised, isolated from wild stocks But even during farming of wild type fish, escapes happen frequently (~14 million/yr) What would happen if a large number of transgenic escaped & started breeding with wild fish? http: //pewagbiotech. org/buzz/index. php 3? Issue. ID=10
In experiments, transgenic males mated 3 x more frequently than the smaller wild males Offspring of transgenic males lived <70% as long as wild males Could lead to a decline of the wild fish population & endanger a species as whole
Antifreeze Proteins (AFP) AFPs lower the freezing temperature of blood & fluids Trout normally do not survive in water below – 0. 6°C Transgenic trout containing an AFP gene & promoter can survive in waters as cold as – 1. 2°C wild transgenic http: //pubs. acs. org/hotartcl/chemtech/99/jun/fletcher. htm
This is a genetically modified strain of malaria-resistant mosquito which has been created successfully by a scientist. The creation of mosquitoes with green fluorescent testicles will help curb the spread of malaria-carrying mosquitoes.
Animal Bioreactors “Pharming”
GMO medicine: E. Coli with the human insulin gene - Insulin is made using the bacterium E. coli. - The human gene coding for insulin is inserted into E. coli, which will then make insulin for us (we will see how this is done shortly)…
GMO medicine: AAT Sheep Genetically engineered sheep with the human gene for alpha-1 antitrypsin (AAT). AAT is extracted from their milk and used to treat humans deficient in AAT, which is one cause of emphysema (a breathing disorder) in approximately 100, 000 people in the western world.
GMO’s and medicine: • Transgenic cows can make serum albumin for treatment of burns and severe trauma to tissue
Other Types of Transgenic Animals
Spider silk • Spider’s silk is 5 times stronger than a thread of steel of the same thickness 3 times stronger than Kevlar (carbon fibre) • Spiders are carnivores and cannot be raised • Transgenic animals can produce the spider protein © 2010 Paul Billiet ODWS © P. Billiet Aculepeira ceropegia a European orbweb spider
Spider silk • The gene for spider silk protein was isolated from the golden orb weaver (Nephila clavipes) • It is a fibrous protein so it has a very repetitive gene sequence © 2010 Paul Billiet ODWS Nephila clavipes © C. Frank Starmer
Web-based kid Spider goat © Sean O'Neill • Gene (plus regulator genes) inserted into goat mammary gland cells • Genetically transformed cells could be made to secrete spider silk protein • Transformed goat cells fused to enucleated oocyte • Genetically transformed goat embryos produced © 2010 Paul Billiet
Applications • • Super strong surgery thread Artificial ligaments Light bullet proof body armor Biodegradable fishing line © 2010 Paul Billiet ODWS
ANDi, the first transgenic primate born in Jan 2000 224 unfertilized rhesus eggs were infected with a GFP virus ~Half of the fertilized eggs grew and divided 40 were implanted into twenty surrogate mothers five males were born, two were stillborn ANDi was the only live monkey carrying the GFP gene http: //www. ohsu. edu/unparchive/2001/011001 andi. shtm
Alba, the EGFP (enhanced GFP) bunny Created in 2000 as a transgenic artwork http: //www. ekac. org/gfpbunny. html#gfpbunnyancho
Researchers transfer DNA from the long-vanished Tasmanian tiger into a mouse. The finding shows how lost information about species from the past can be retrieved and also provides a glimpse into how long-gone creatures may someday get a second chance at life.
Mouse “Knock-out” Technology Gene Targeting
Knock-out technology allows for the specific loss of a gene in mice Allows for the function of the KO’d gene to be deduced from the defects seen in the mice Can be used to mimic some disease Unlike traditional transgenics, the trangene is targeted to a specific site in the DNA of the mouse
Mouse Knock-outs require embryonic stem (ES) cells These are derived from the inner cell mass (ICM) of a blastocyst (the ICM is what will become the fetus) ES cells are pluripotent meaning they can become all the different cell types found in an adult http: //cba. musc. edu/SC_COBRE/CORE-B/Resources-B. htm
Chimeric mouse The brown fur comes from ES cells injected into the blastocyst of an albino mouse http: //bunseiserver. pharm. hokudai. ac. jp/gihou/knockout. ht
Some Examples of Knockout Organisms
p 27 knockout mouse is bigger than the control This is not due to obesity, but the skeletal structure is increased in size (everything about the mouse is larger) http: //www. bioreg. kyushu-u. ac. jp/saibou. E. htm
normal knockout GDF 8 (Myostatin) knockout mouse Over twice the muscle mass of a wild type mouse http: //www. bbc. co. uk/science/genes/gene_safari/wild_west/bigger_and_better 02. shtm
Naturally Occurring GDF 8 Mutants http: //www. canada. com/victoriatimescolonist/story. html? id=67 f 15 c 17 -2717 -4022 -bb 76 -1 b 982456 e 793&k=946 http: //www. bbc. co. uk/science/genes/gene_safari/wild_west/bigger_and_better 02. shtml
Conclusion - We can basically move any gene(s) between members of a species or between any species. - We can also alter the genes to our liking (GFP tagged proteins) before inserting them into embryos. Is all of this genetic engineering positive or negative?