It has been suggested that Transformation (genetics) be merged into this article or section. (Discuss)

Transfection describes the introduction of foreign material into eukaryotic cells. Transfection typically involves opening transient pores or 'holes' in the cell plasma membrane, to allow the uptake of material. Genetic material (such as supercoiled plasmid DNA or siRNA constructs), or even proteins such as antibodies, may be transfected. In addition to electroporation, transfection can be carried out by mixing a cationic lipid with the material to produce liposomes, which fuse with the cell plasma membrane and deposit their cargo inside. Image File history File links Mergefrom. ... It has been suggested that this article or section be merged into Transfection. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Chromalveolata Protista Alternative phylogeny Unikonta Opisthokonta Metazoa Choanozoa Eumycota Amoebozoa Bikonta Apusozoa Cabozoa Rhizaria Excavata Corticata Archaeplastida Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. ... Drawing of a cell membrane A component of every biological cell, the cell membrane (or plasma membrane) is a thin and structured bilayer of phospholipid and protein molecules that envelopes the cell. ... Supercoiled structure of circular DNA molecules with low writhe. ... Small interfering RNA (siRNA) are a class of 20-25 nucleotide-long RNA molecules that interfere with the expression of genes. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Wikipedia does not yet have an article with this exact name. ... Electroporation, or electropermeabilization, is a significant increase in the electrical conductivity and permeability of the cell plasma membrane caused by externally applied electrical field. ... In chemistry, a cationic species is one that contains a full positive charge. ... Some common lipids. ... A liposome is a spherical vesicle with a membrane composed of a phospholipid bilayer used to deliver drugs or genetic material into a cell. ...

The term transfection is most often used in reference to mammalian cells, while the term transformation is used for the same process in bacteria and, occasionally, plants. The original meaning of transfection was 'infection by transformation', i.e. introduction of DNA (or RNA) from a eukaryote virus or bacteriophage into cells, resulting in an infection. Because the term transformation had another sense in eukaryotic cell biology (a genetic change allowing long-term propagation in culture, or acquisition of properties typical of cancer cells), the term transfection acquired, for animal cells, its present meaning of a change in cell properties caused by introduction of DNA. It has been suggested that this article or section be merged into Transfection. ...

Methods

There are various methods of introducing foreign DNA into a eukaryote cell. One of the cheapest (and least reliable) is transfection by calcium phosphate, originally discovered by S. Bacchetti and F. L. Graham in 1977.^[1] HEPES-buffered saline solution (HeBS) containing phosphate ions is combined with a calcium chloride solution containing the DNA to be transfected. When the two are combined, a fine precipitate of calcium phosphate will form, binding the DNA to be transfected on its surface. The suspension of the precipitate is then added to the cells to be transfected (usually a cell culture grown in a monolayer). By a process not entirely understood, the cells take up some of the precipitate, and with it, the DNA. Other methods of transfection include electroporation, heat shock, magnetofection and proprietary transfection reagents such as Lipofectamine, Fugene, jetPEI or DreamFect. The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... Calcium phosphate is the name given to a family of minerals containing calcium ions (Ca2+) together with orthophosphates (PO43-), metaphosphates or pyrophosphates (P2O74-) and occasionally hydrogen or hydroxide ions. ... Hepes (4-2-hydroxyethyl-1-piperazineethanesulfonic acid ) is an organic chemical buffer which is widely used in cell culture to maintain physiological pH. Its molecular weight is 238. ... R-phrases S-phrases , , Related Compounds Other anions calcium fluoride calcium bromide calcium iodide Other cations magnesium chloride strontium chloride Supplementary data page Structure and properties n, εr, etc. ... Electroporation, or electropermeabilization, is a significant increase in the electrical conductivity and permeability of the cell plasma membrane caused by externally applied electrical field. ... Heat shock proteins are a part of the cells internal repair mechanism. ... Magnetofection is a simple and highly efficient transfection method that uses magnetic fields to concentrate particles containing nucleic acid into the target cells. ... Lipofectamine or Lipofectamine 2000 is a common transfection reagent, produced and sold by Invitrogen, used in molecular and cellular biology. ...

Other methods use highly branched organic compounds, so-called dendrimers, to bind the DNA and get it into the cell. A very efficient method is the inclusion of the DNA to be transfected in liposomes, i.e. small, membrane-bounded bodies that are in some ways similar to the structure of a cell and can actually fuse with the cell membrane, releasing the DNA into the cell. For eukaryotic cells, lipid-cation based transfection is more typically used, because the cells are more sensitive. A dendrimer is a molecule with a form like the branches of a tree. ... A liposome is a spherical vesicle with a membrane composed of a phospholipid bilayer used to deliver drugs or genetic material into a cell. ... Look up cell membrane in Wiktionary, the free dictionary. ...

Another method is DEAE-Dextran transfection, in which a mutant plasmid and Luciferase reporter are used. Dextran is positively charged. A cell performs endocytosis to take in the positively charged Dextran, which is attracted to the DNA (negatively charged).

Many materials have been used as carries for transfection, which can be divided into three kinds: polymers,nanoparticles and liposomes.

A direct approach to transfection is the gene gun, where the DNA is coupled to a nanoparticle of an inert solid (commonly gold) which is then "shot" directly into the target cell's nucleus. DNA can also be introduced into cells using viruses as a carrier. In such cases, the technique is called viral transduction, and, the cells are said to be transduced. The gene gun is a device for injecting cells with genetic information, originally designed for plant transformation. ... It has been suggested that nanopowder be merged into this article or section. ... In English, to be inert is to be in a state of doing little or nothing. ... HeLa cells stained for DNA with the Blue Hoechst dye. ... This article is about biological infectious particles. ... Transduction is the process by which bacterial DNA is moved from one bacterium to another by a virus. ...

Stable and transient transfection

For most applications of transfection, it is sufficient if the transfected gene is only transiently expressed. Since the DNA introduced in the transfection process is usually not inserted into the nuclear genome, the foreign DNA is lost at the later stage when the cells undergo mitosis. If it is desired that the transfected gene actually remains in the genome of the cell and its daughter cells, a stable transfection must occur. Mitosis divides genetic information during cell division. ...

To accomplish this, another gene is co-transfected, which gives the cell some selection advantage, such as resistance towards a certain toxin. Some (very few) of the transfected cells will, by chance, have inserted the foreign genetic material into their genome. If the toxin, towards which the co-transfected gene offers resistance, is then added to the cell culture, only those few cells with the foreign genes inserted into their genome will be able to proliferate, while other cells will die. After applying this selection pressure for some time, only the cells with a stable transfection remain and can be cultivated further. For other uses, see Selection (disambiguation). ... For other uses, see Toxin (disambiguation). ... The term cell growth is used in two different ways in biology. ... For other uses, see Selection (disambiguation). ...

A common agent for stable transfection is Geneticin, also known as G418, which is a toxin that can be neutralized by the product of the neomycin resistant gene. G418 (also known as Geneticin) is an aminoglycoside antibiotic similar in structure to gentamicin B1. ... Neomycin is an aminoglycoside antibiotic that is found in many topical medications such as creams, ointments and eyedrops. ...

References

1. ^ Bacchetti S, Graham F (1977). "Transfer of the gene for thymidine kinase to thymidine kinase-deficient human cells by purified herpes simplex viral DNA". Proc Natl Acad Sci U S A 74 (4): 1590-4. PMID 193108. 

See also

• Protofection
• Transformation
• Transduction

Protofection is a term that refers to the transfection of foreign mitrochondria to replace the original energy generators within cells. ... It has been suggested that this article or section be merged into Transfection. ... Transduction is the process by which bacterial DNA is moved from one bacterium to another by a virus. ...

External links

• Cell Transfection Protocol at biologicalworld.com
• MeSH Transfection
• Transfection at eMedicine Dictionary