Editing Expression vector (section)

==Applications==

===Laboratory use===
Expression vector in an expression host is now the usual method used in laboratories to produce proteins for research. Most proteins are produced in ''E. coli'', but for glycosylated proteins and those with disulphide bonds, yeast, baculovirus and mammalian systems may be used.

===Production of peptide and protein pharmaceuticals===
Most protein [[pharmaceuticals]] are now produced through recombinant DNA technology using expression vectors. These peptide and protein pharmaceuticals may be hormones, vaccines, antibiotics, antibodies, and enzymes.<ref name="pharmaceutical">{{cite book |url=https://books.google.com/books?id=ZhlApPkxpuAC&pg=PA693 |title=Handbook of Pharmaceutical Biotechnology |author=Shayne Cox Gad |page=693 |publisher=John Wiley & Sons |year=2007 |isbn= 978-0-471-21386-4 }}</ref>  The first human recombinant protein used for disease management, insulin, was introduced in 1982.<ref name="pharmaceutical"/> Biotechnology allows these peptide and protein pharmaceuticals, some of which were previously rare or difficult to obtain, to be produced in large quantity. It also reduces the risks of contaminants such as host viruses, toxins and [[prions]]. Examples from the past include [[prion]] contamination in [[growth hormone]] extracted from [[pituitary gland]]s harvested from human cadavers, which caused [[Creutzfeldt–Jakob disease]] in patients receiving treatment for [[dwarfism]],<ref>{{cite journal |title=Parents sue over contaminated human growth hormone |author=Alexander Dorozynski |journal=British Medical Journal |year=2002 |volume= 324 |issue=7349 |page=1294|pmc=1123268 |pmid=12039815 |doi=10.1136/bmj.324.7349.1294/b}}</ref> and viral contaminants in clotting [[factor VIII]] isolated from human blood that resulted in the transmission of viral diseases such as [[hepatitis]] and [[AIDS]].<ref>{{cite book |url=https://books.google.com/books?id=ZhlApPkxpuAC&pg=PA738 |title=Handbook of Pharmaceutical Biotechnology |author=Shayne Cox Gad |page=738 |publisher=John Wiley & Sons |isbn= 978-0-471-21386-4 |date=2007-05-25 }}</ref><ref>{{cite journal | url = https://query.nytimes.com/gst/fullpage.html?res=9A00E4DA1F3EF931A15756C0A9659C8B63&sec=&spon=&pagewanted=1=2157 | title = 2 Paths of Bayer Drug in 80's: Riskier One Steered Overseas |vauthors=Bogdanich W, Koli E | date = 2003-05-22 | journal = The New York Times | pages = A1, C5 | pmid = 12812170 }}</ref> Such risk is reduced or removed completely when the proteins are produced in non-human host cells.

===Transgenic plant and animals===

In recent years, expression vectors have been used to introduce specific genes into plants and animals to produce [[transgenic]] organisms, for example in [[agriculture]] it is used to produce [[transgenic plants]]. Expression vectors have been used to introduce a [[vitamin A]] precursor, [[beta-carotene]], into rice plants. This product is called [[golden rice]]. This process has also been used to introduce a gene into plants that produces an [[insecticide]], called [[Bacillus thuringiensis|Bacillus thuringiensis toxin]] or [[Bacillus thuringiensis|Bt toxin]] which reduces the need for farmers to apply insecticides since it is produced by the modified organism. In addition expression vectors are used to extend the ripeness of tomatoes by altering the plant so that it produces less of the chemical that causes the tomatoes to rot.<ref>{{Cite web |url=http://www.bionetonline.org/english/content/ff_cont3.htm |title=bionetonline.org |access-date=2010-06-12 |archive-url=https://web.archive.org/web/20100617043538/http://www.bionetonline.org/english/content/ff_cont3.htm |archive-date=2010-06-17 }}</ref> There have been [[Genetically modified food controversies|controversies]] over using expression vectors to modify crops due to the fact that there might be unknown health risks, possibilities of companies patenting certain [[genetically modified food]] crops, and ethical concerns. Nevertheless, this technique is still being used and heavily researched.

[[Transgenic animals]] have also been produced to study animal biochemical processes and human diseases, or used to produce pharmaceuticals and other proteins. They may also be engineered to have advantageous or useful traits. [[Green fluorescent protein]] is sometimes used as tags which results in animal that can fluoresce, and this have been exploited commercially to produce the fluorescent [[GloFish]].

===Gene therapy===
{{main|Vectors in gene therapy}}
[[Gene therapy]] is a promising treatment for a number of diseases where a "normal" gene carried by the vector is inserted into the genome, to replace an "abnormal" gene or supplement the expression of particular gene. Viral vectors are generally used but other nonviral methods of delivery are being developed. The treatment is still a risky option due to the viral vector used which can cause ill-effects, for example giving rise to [[insertional mutation]] that can result in cancer.<ref>{{cite web |url=http://www.ornl.gov/sci/techresources/Human_Genome/medicine/genetherapy.shtml |title=Gene therapy |work=Human Genome Project }}</ref><ref>{{cite news |url=https://www.theguardian.com/society/2003/oct/17/research.sciencenews |title=Doctors discover why gene therapy gave boys cancer |author=Ian Sample |work=Guardian |date=17 October 2003 }}</ref> However, there have been promising results.<ref>{{cite news |url=https://www.theguardian.com/science/2013/apr/30/gene-therapy-trials-heart-patients|title= Pioneering gene therapy trials offer hope for heart patients|author=Sarah Boseley |work=Guardian |date=30 April 2013 }}</ref><ref>{{Cite journal | last1 = Fischer | first1 = A. | last2 = Hacein-Bey-Abina | first2 = S. | last3 = Cavazzana-Calvo | first3 = M. | doi = 10.1038/ni0610-457 | title = 20 years of gene therapy for SCID | journal = Nature Immunology | volume = 11 | issue = 6 | pages = 457–460 | year = 2010 | pmid = 20485269| s2cid = 11300348 }}</ref>