Transgene Expression Lecture PDF

Transgene Expression  Introduction TRANSGENE- It is a foreign gene or genetic material that has been transferred naturally or by any of a number of genetic engineering techniques from one organism to another. TRANSGENESIS- The phenomenon of introduction of exogenous DNA into th...

Transgene Expression  Introduction TRANSGENE- It is a foreign gene or genetic material that has been transferred naturally or by any of a number of genetic engineering techniques from one organism to another. TRANSGENESIS- The phenomenon of introduction of exogenous DNA into the genome to create and maintain a stable and heritable character. Transgenesis has the potential to change the phenotype of an organism TRANSGENIC PLANTS/Animals- The plant/animals whose genome is altered by adding one or more transgenes are known as transgenic plants.  History 1982 - 1st transgenic plant produced which is an antibiotic resistance tobacco plant. 1984 - 1st successful plant genetic engineering experiments using caulimovirus vector. 1994 - 1st genetically modified crop approved for sale in U.S. was FlavrSavr tomato. 1995 - 1st pesticide producing crop, Bt Potato was approved by U.S. Environmental Protection Agency 1996 - 1st genetically modified flower Moondust, bluish colored carnation, was introduced. 2000 - Golden rice with β- carotene developed with increased nutrient value. 2013 - 1st genetically engineered crop developed by Robert Fraley, Marc Van Montagu &Marry Dell Chilton were awarded World Food Prize. Transgenic Organisms 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) GMO’s at home: Zebra danio GloFish 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 protein 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  Green fluorescent protein (GFP) Green fluorescent protein (GFP) is a protein in the jellyfish Aequorea Victoria that exhibits green fluorescence when exposed to light The protein has 238 amino acids, three of them (Numbers 65 to 67) form a structure that emits visible green fluorescent light In the jellyfish, GFP interacts with another protein, called aequorin, which emits blue light when added with calcium Biologists use GFP to study cells in embryos and fetuses during developmental processes  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/v19/n6/images/nbt0601_500a_I1.jpg The transgene used to increase growth utilizes an antifreeze protein promoter connected to the GH cDNA 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.html  Embryonic Stem Cell-Mediated Gene Transfer This method involves:  Isolation of stem cells from embryos  The desired gene is inserted into these cells  Cells containing the desired DNA are incorporated into the host’s embryo, resulting in a chimeric animal.  MEDICAL Gene therapy  Process in which healthy genes are inserted in the person’s body in place of defected genes that might cause diseases  Scientists of Finland have developed a calf which carries a gene that responsible for making a substance which promotes the growth of red blood cells in humans. Pharmaceuticals  Production of insulin, growth hormones and blood clotting factors in the transgenic animals  These are obtained from cow, goats or sheep’s milk through transgenesis to treat the diseases like cystic fibrosis and phenylketonuria  MEDICAL Xenotransplantation  A surgical procedure in which tissue or whole organs are transferred from one species to another species  Scientist successfully done experiments in pigs and developed human organ. But there is a protein in pig which cannot be accepted by human immune system  Now they are working on this problem and trying to replace this protein with the human protein that can easily accepted by the human immune system  AGRICULTURAL Breeding  Farmers breed the animals selectively to obtained healthy animals that have the required traits for example, increased amount of milk and healthy meat  Beneficial for farmers to get the higher yield in short time Disease resistance  Diseases like influenza can cause damage to the animal body, so that the genes that show resistant against this disease was inserted into animal body  To avoid the disease spreads from one animal to the other Quality  Transgenic cows are able to produce milk which has more nutritional value than an ordinary cow’s milk  INDUSTRIAL  Two scientists of Canada have successfully inserted spider genes into goats which are lactating  Along the milk production, goats will also produce silk which is a light flexible material used to make tennis rackets, medicine micro sutures and army uniforms  For the safety of chemicals, scientist have produced toxicity sensitive transgenic animals  Many proteins have produced by using transgenic animals which in turn convert into enzymes to perform different functions in the body.