Difference between revisions of "Transfection" - New World Encyclopedia

From New World Encyclopedia
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[[Image:genegun.jpg|thumb|PSD-1000/He Particle Delivery System. The ''gene gun'' or the Biolistic Particle Delivery System, originally designed for [[plant]] [[transformation (genetics)|transformation]], is a device for injecting cells with [[genetics|genetic]] information]]
 
[[Image:genegun.jpg|thumb|PSD-1000/He Particle Delivery System. The ''gene gun'' or the Biolistic Particle Delivery System, originally designed for [[plant]] [[transformation (genetics)|transformation]], is a device for injecting cells with [[genetics|genetic]] information]]
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Broadly defined, '''transfection''' is the process of artificially introducing [[nucleic acid]]s ([[DNA]] or [[RNA]]) into [[cell (biology)|cells]], utilizing means other than [[virus|viral]] infection. Such introductions of foreign nucleic acid into a cell can result in a change of the properties of the cell and the intent of a transfection is for the introduced DNA or RNA to be expressed.  
+
Broadly defined, '''transfection''' is the process of artificially introducing [[nucleic acid]]s ([[DNA]] or [[RNA]]) into [[cell (biology)|cells]], utilizing means other than [[virus|viral]] infection. Such introductions of foreign nucleic acid can result in a change of the properties of the cell.  
  
−
The term transfection also is used more narrowly to refer to non-viral introductions of nucleic acid specifically into [[eukaryote|eukaryotic]] cells, or to refer to infecting a cell with viral nucleic acid that is either isolated from a eukaryote virus or from a [[bacteriophage]] (a virus that infects bacteria). Conversely, the term also has been used to refer to infecting a bacterial cell with viral DNA, resulting in multiplication of mature viral particles. However, the term transfection generally now is used for any artificial introduction of foreign nucleic acid into a cell. The term [[transformation (genetics)|transformation]] is preferred to describe non-viral [[DNA]] transfer in [[bacteria]] and non-animal eukaryotic cells such as [[fungus|fungi]], [[alga]]e, and [[plant]]s.  
+
The term transfection also is used more narrowly to refer to non-viral introductions of nucleic acid specifically into [[eukaryote|eukaryotic]] cells, or to refer to infecting a cell specifically with viral nucleic acid that is either isolated from a eukaryote virus or from a [[bacteriophage]] (a virus that infects bacteria). While classically the term was used to refer to infecting a bacterial cell with viral DNA, resulting in multiplication of mature viral particles, the term now generally is used for any artificial introduction of foreign nucleic acid into a cell. The term [[transformation (genetics)|transformation]] often is preferred to describe non-viral [[DNA]] transfer in [[bacteria]] and non-animal eukaryotic cells such as [[fungus|fungi]], [[alga]]e, and [[plant]]s.  
  
−
In transfection, the introduced nucleic acid may be transient, such that it does not replicate, or it may be stable and integrate into the genome of the recipient and replicate when the host genome replicates.
+
In transfection, the introduced nucleic acid may be transient, such that it does not replicate, or it may be stable and integrate into the [[genome]] of the recipient and replicate when the host genome replicates.
  
 
There are many methods employed in performing transfection. Transfection of [[animal cell]]s typically involves opening transient pores or “holes” in the cell [[plasma membrane]], to allow the uptake of material. [[Genetics|Genetic]] material (such as [[DNA supercoil|supercoiled plasmid DNA]] or [[siRNA]] constructs), or even sections of DNA coding for [[protein]]s such as [[antibody|antibodies]], may be transfected. In addition to [[electroporation]], transfection can be carried out using [[calcium phosphate]], or by mixing a [[cationic]] [[lipid]] with the material to produce [[liposome]]s, which fuse with the cell plasma membrane and deposit their cargo inside.   
 
There are many methods employed in performing transfection. Transfection of [[animal cell]]s typically involves opening transient pores or “holes” in the cell [[plasma membrane]], to allow the uptake of material. [[Genetics|Genetic]] material (such as [[DNA supercoil|supercoiled plasmid DNA]] or [[siRNA]] constructs), or even sections of DNA coding for [[protein]]s such as [[antibody|antibodies]], may be transfected. In addition to [[electroporation]], transfection can be carried out using [[calcium phosphate]], or by mixing a [[cationic]] [[lipid]] with the material to produce [[liposome]]s, which fuse with the cell plasma membrane and deposit their cargo inside.   
  
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importance:
+
The intent of a transfection is for the introduced DNA or RNA to be expressed. This process allows a variety of important applications, including the study of gene regulation, the analysis of the expression of proteins within eukarotic cells such as those of mammals, the production of transgenic organisms, and the methods of gene therapy.
−
gene regulation
 
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analysis of expresson and function of proteins within eukarotic cells, such as mammalinan cells,
 
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production of transgenic organsims
 
−
gene therapy strategies
 
−
 
 
  
 
==Terminology==
 
==Terminology==
−
The meaning of the term transfection has changed over time. Originally, the term was used for the artificial insertion of viral [[nucleic acid]] into [[bacteria]]l cells, yield mature virus particles  (Dorland 2007a). It also was used in the sense of "infection by transformation", in other words, introduction of DNA (or RNA) from an eukaryote virus or [[bacteriophage]] into cells, resulting in an infection.  Because the term transformation had another sense in animal 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 nucleic acids by non-viral methods. It now includes any means of artificial introduction of foreign DNA into cultured eukaryotic cells. Weinberg et al. (1990) state that the meaning is clear and unambiguous to refer to the "process by which nucleic acid (DNA or RNA) is introduced to cells with the intent to be expressed in the recipient."
+
The meaning of the term transfection has changed over time. Originally, the term was used for the artificial insertion of viral [[nucleic acid]] into [[bacteria]]l cells, yield mature virus particles  (Dorland 2007a). It also was used in the sense of "infection by transformation", in other words, introduction of DNA (or RNA) from an eukaryote virus or [[bacteriophage]] into cells, resulting in an infection.  Because the term transformation had another sense in animal 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 nucleic acids by non-viral methods. It now includes any means of artificial introduction of foreign DNA into cells, or more specifically cultured eukaryotic cells. Weinberg et al. (1990) state that the meaning of transfection is "clear and unambiguous" and refers to the "process by which nucleic acid (DNA or RNA) is introduced to cells with the intent to be expressed in the recipient."
−
 
 
−
 
 
−
The transfection process is distinct from “infection”, which is a viral
 
−
method of nucleic acid introduction into cells (Promega).
 
  
−
The term is analogous to the term transformation, However, that term remains ambiguous. In [[molecular biology]], the term transformation has been used in the related sense to the genetic alteration of a [[cell (biology)|cell]] resulting from the uptake, genomic incorporation, and expression of foreign [[gene]]tic material ([[DNA]]) (Dorland 2007b). However, transformation also is used in other senses as well including to the non-viral nuclic acid transfer in [[bacteria]] and non-animal eukaryotic cells such as [[fungus|fungi]], [[alga]]e, and [[plant]]s. Transformation of eukaryotic cells in [[tissue culture]] is usually called transfection.  
+
The transfection process is distinct from “infection”, which is a viral method of nucleic acid introduction into cells (Promega).
  
 +
The term transfection is analogous to the term transformation, However, that latter term remains ambiguous. In [[molecular biology]], the term transformation has been used in the related sense to refer to the genetic alteration of a [[cell (biology)|cell]] resulting from the uptake, genomic incorporation, and expression of foreign [[gene]]tic material ([[DNA]]) (Dorland 2007b). However, transformation also is used in other senses as well, including to the non-viral nucleic acid uptake specifically in [[bacteria]] and non-animal eukaryotic cells such as [[fungus|fungi]], [[alga]]e, and [[plant]]s. Transformation of eukaryotic cells in [[tissue culture]] is usually called transfection.
  
 
Separate terms are used for genetic alterations resulting from introduction of DNA by viruses ("[[transduction (genetics)|transduction]]") or by cell-cell contact between bacteria ("[[bacterial conjugation|conjugation]]").  
 
Separate terms are used for genetic alterations resulting from introduction of DNA by viruses ("[[transduction (genetics)|transduction]]") or by cell-cell contact between bacteria ("[[bacterial conjugation|conjugation]]").  
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−
 
−
 
−
 
−
 
  
 
==Methods==
 
==Methods==
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Other methods of transfection include [[nucleofection]], [[electroporation]], [[sonoporation]], [[heat shock]], [[magnetofection]], and proprietary transfection reagents such as [[Lipofectamine]], [[Dojindo]] Hilymax, Fugene, jetPEI, Effectene, or DreamFect.
 
Other methods of transfection include [[nucleofection]], [[electroporation]], [[sonoporation]], [[heat shock]], [[magnetofection]], and proprietary transfection reagents such as [[Lipofectamine]], [[Dojindo]] Hilymax, Fugene, jetPEI, Effectene, or DreamFect.
  
−
 
+
Transfection techniques can be broadly classified as chemical reagents and physical methods. Chemical reagents include such as DEAE-dextran and calcium phosphate. Physical methods include such as electroporation (perturbing the cell membrane by an electrical pulse, forming pores), direct microinjection, and biolistic particle delivery (high velocity delivery of nucleic acids).
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:The
 
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techniques developed for gene transfer can be
 
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broadly classified as either chemical reagents or
 
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physical methods.
 
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Chemical Reagents
 
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DEAE-dextran was one of the first chemical reagents
 
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used for transfer of nucleic acids into cultured
 
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mammalian cells (1,9).
 
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Calcium phosphate co
 
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physical
 
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Direct microinjection into cultured cells or nuclei is
 
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an effective, although
 
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Electroporation was first reported for gene transfer
 
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studies in 1982 (4). This technique is often used
 
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for cell types such as plant protoplasts that are
 
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particularly recalcitrant to milder methods of gene
 
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transfer. The mechanism for entry into the cell is
 
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based upon perturbation of the cell membrane by
 
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an electrical pulse, which forms pores that allow the
 
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passage of nucleic acids into the cell
 
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Another physical method of gene delivery is
 
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biolistic particle delivery. This method relies upon high
 
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velocity delivery of nucleic acids on microprojectiles
 
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to recipient cells
 
  
 
==Stable and transient transfection==
 
==Stable and transient transfection==
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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.
 
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.
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An example of such a combination is the marker
 
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gene for neomycin phosphotransferase with the
 
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drug Geneticin® (8).
 
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==See also==
 
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*[[Protofection]]
 
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*[[Transformation (genetics)|Transformation]]
 
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*[[Transduction (genetics)|Transduction]]
 
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*[[Cationic liposome]]
 
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*[[Nucleofection]]
 
  
 
==References==
 
==References==

Revision as of 07:26, 22 February 2009

PSD-1000/He Particle Delivery System. The gene gun or the Biolistic Particle Delivery System, originally designed for plant transformation, is a device for injecting cells with genetic information

Broadly defined, transfection is the process of artificially introducing nucleic acids (DNA or RNA) into cells, utilizing means other than viral infection. Such introductions of foreign nucleic acid can result in a change of the properties of the cell.

The term transfection also is used more narrowly to refer to non-viral introductions of nucleic acid specifically into eukaryotic cells, or to refer to infecting a cell specifically with viral nucleic acid that is either isolated from a eukaryote virus or from a bacteriophage (a virus that infects bacteria). While classically the term was used to refer to infecting a bacterial cell with viral DNA, resulting in multiplication of mature viral particles, the term now generally is used for any artificial introduction of foreign nucleic acid into a cell. The term transformation often is preferred to describe non-viral DNA transfer in bacteria and non-animal eukaryotic cells such as fungi, algae, and plants.

In transfection, the introduced nucleic acid may be transient, such that it does not replicate, or it may be stable and integrate into the genome of the recipient and replicate when the host genome replicates.

There are many methods employed in performing transfection. Transfection of animal cells 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 sections of DNA coding for proteins such as antibodies, may be transfected. In addition to electroporation, transfection can be carried out using calcium phosphate, or by mixing a cationic lipid with the material to produce liposomes, which fuse with the cell plasma membrane and deposit their cargo inside.

The intent of a transfection is for the introduced DNA or RNA to be expressed. This process allows a variety of important applications, including the study of gene regulation, the analysis of the expression of proteins within eukarotic cells such as those of mammals, the production of transgenic organisms, and the methods of gene therapy.

Terminology

The meaning of the term transfection has changed over time. Originally, the term was used for the artificial insertion of viral nucleic acid into bacterial cells, yield mature virus particles (Dorland 2007a). It also was used in the sense of "infection by transformation", in other words, introduction of DNA (or RNA) from an eukaryote virus or bacteriophage into cells, resulting in an infection. Because the term transformation had another sense in animal 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 nucleic acids by non-viral methods. It now includes any means of artificial introduction of foreign DNA into cells, or more specifically cultured eukaryotic cells. Weinberg et al. (1990) state that the meaning of transfection is "clear and unambiguous" and refers to the "process by which nucleic acid (DNA or RNA) is introduced to cells with the intent to be expressed in the recipient."

The transfection process is distinct from “infection”, which is a viral method of nucleic acid introduction into cells (Promega).

The term transfection is analogous to the term transformation, However, that latter term remains ambiguous. In molecular biology, the term transformation has been used in the related sense to refer to the genetic alteration of a cell resulting from the uptake, genomic incorporation, and expression of foreign genetic material (DNA) (Dorland 2007b). However, transformation also is used in other senses as well, including to the non-viral nucleic acid uptake specifically in bacteria and non-animal eukaryotic cells such as fungi, algae, and plants. Transformation of eukaryotic cells in tissue culture is usually called transfection.

Separate terms are used for genetic alterations resulting from introduction of DNA by viruses ("transduction") or by cell-cell contact between bacteria ("conjugation").

Methods

There are various methods of introducing foreign DNA into a eukaryotic cell. Many materials have been used as carriers for transfection, which can be divided into three kinds: (cationic) polymers, liposomes, and nanoparticles.

One of the cheapest (and least reliable) methods is transfection by calcium phosphate, originally discovered by F. L. Graham and A. J. van der Eb and reported on in 1973 (Graham and Eb 1973; Bacchetti and Graham 1977. 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 the positively charged calcium and the negatively charged 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 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, in other words, 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.

Another method is the use of cationic polymers such as DEAE-dextran or polyethylenimine. The negatively charged DNA binds to the polycation and the complex is taken up by the cell via endocytosis.

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.

Of course, DNA also can 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.

Other methods of transfection include nucleofection, electroporation, sonoporation, heat shock, magnetofection, and proprietary transfection reagents such as Lipofectamine, Dojindo Hilymax, Fugene, jetPEI, Effectene, or DreamFect.

Transfection techniques can be broadly classified as chemical reagents and physical methods. Chemical reagents include such as DEAE-dextran and calcium phosphate. Physical methods include such as electroporation (perturbing the cell membrane by an electrical pulse, forming pores), direct microinjection, and biolistic particle delivery (high velocity delivery of nucleic acids).

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. 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.

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.

References
ISBN links support NWE through referral fees

  • Alberts, B., D. Bray, J. Lewis, M. Raff, K. Roberts, and J. D. Watson. 1989. Molecular Biology of the Cell, 2nd edition. New York: Garland Publishing. ISBN 0824036956.

http://www.mercksource.com/pp/us/cns/cns_hl_dorlands_split.jsp?pg=/ppdocs/us/common/dorlands/dorland/eight/000110186.htm

Dorland 2007b transformation

  • Graham, F. L., and A. J. van der Eb. 1973. A new technique for the assay of infectivity of human adenovirus 5 DNA. Virology 52(2): 456–67. PMID 4705382.
|doi=10.1016/0042-6822(73)90341-3}}
  • Bacchetti, S. and F. L. Graham. 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

Promega. n.d. http://www.promega.com/guides/transfxn_guide/transfxn.pdf Transfection


Transfection' vs 'Transformation': Defining Terms Author: Seeber F. Source: Parasitology Today, Volume 16, Number 9, 1 September 2000 , pp. 404-404(1) http://www.ncbi.nlm.nih.gov/pubmed/10951602

Robert A. Weinberg1, Ruth Sager2, Stuart A. Aaronson3, Warren I. Schaeffer4 and Leonard Hayflick5 http://www.springerlink.com/content/cp820l465042x524/ In the interest of clearer communication Journal In Vitro Cellular & Developmental Biology - Plant Volume 26, Number 1 / January, 1990

External links


Genetics: genetic recombination / mobile genetic elements
Primarily prokaryotic
Conjugation · Transduction · Transformation · Transposon
Occurs in eukaryotes
Transfection · Chromosomal crossover · Gene conversion · Fusion gene · Horizontal gene transfer · Sister chromatid exchange

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