Transgene Expression and History

Transgene Expression

• Transgene: A foreign gene or genetic material transferred from one organism to another, either naturally or via genetic engineering.
• Transgenesis: The process of introducing exogenous DNA into an organism's genome to create a stable and heritable trait. This has the potential to alter the organism's phenotype.
• Transgenic Plants/Animals: Organisms whose genomes have been altered by introducing one or more transgenes.

Introduction

• Transgene Definition: A foreign gene or genetic material transferred from one organism to another.
• Transgenesis Definition: Introducing exogenous DNA into an organism's genome to create a permanent heritable trait.
• Transgenic Organisms: Plants or animals with altered genomes that contain transgenes.

History

• 1982: First transgenic plant (antibiotic resistant tobacco plant) is produced.
• 1984: First successful plant genetic engineering experiment using a cauliflower virus vector.
• 1994: First genetically modified crop approved in the US (FlavrSavr tomato).
• 1995: First pesticide-producing crop (Bt Potato) approved.
• 1996: First genetically modified flower (Moondust, bluish carnation) is introduced.
• 2000: Golden rice (with beta-carotene) developed for increased nutrient value.
• 2013: Scientists Robert Fraley, Marc Van Montagu, and Marry Dell Chilton receive the World Food Prize for developing a genetically engineered crop.

Transgenic Organisms

• Image of glowing cats.

Definitions

• Genetically Modified Organisms (GMOs): Organisms whose genes have been altered using genetic engineering techniques.
• Transgenic Organisms: Most GMOs are transgenic, meaning they've received genes from a different organism. Example: A mouse with a human gene.

Embryonic Stem Cell-Mediated Gene Transfer

• Method: Isolates stem cells from embryos, inserts the desired gene, and incorporates these cells into the host embryo, creating a chimeric animal.

GMOs at Home

• GloFish: A zebra danio fish genetically modified with a gene from sea coral. This gene allows the fish to glow in the presence of toxins.

GMOs in Research

• GFP Mice: Mice engineered to express GFP (green fluorescent protein) from jellyfish. This protein is used in research to track the protein's cellular location.
• GFP's use in research: GFP is a reporter protein useful for tracking proteins within cells and organisms.
• GFP and MFD: GFP attached to MFD protein allows scientists to track protein location within peroxisomes.

Green Fluorescent Protein (GFP)

• GFP Source: A protein from the jellyfish Aequorea victoria.
• GFP Function: Emits green fluorescence when exposed to light.
• GFP Structure: Contains 238 amino acids, specifically amino acids 65-67 form a structure which emits green fluorescent light.
• GFP Interactions: Interacts with the protein aequorin in jellyfish, resulting in a blue light emission with the addition of calcium.
• GFP Use: Biologists use GFP to track cell development in embryos and fetuses.

Transgenic Cattle

• Milk Protein Increase: Dairy cows carrying extra casein genes produce 13% more milk protein.
• Nutritional and Processing Benefits: This increase makes milk more nutritious and allows for more efficient cheese production.
• FDA Review: Current milk from these cows is under FDA review.
• DNA Type: The added DNA is not foreign (as in other transgenics).

Transgenic Fish

• Growth Rate Increase: These fish grow up to 6 times faster than wild-type counterparts.
• Growth Hormone Gene (GH): Most transgenic fish have extra copies of the growth hormone (GH) gene.
• Antifreeze Protein Promoter: Transgene that increases growth uses an antifreeze promoter from poutfish connected to salmon growth hormone cDNA coding region. The increased growth happens in cooler water conditions.

Importance

• Agricultural, Medical, Industrial Uses: Transgenic technology has potential to improve human welfare through several fields.