词条 | Knockout mouse |
释义 |
A knockout mouse or knock-out mouse is a genetically modified mouse (Mus musculus) in which researchers have inactivated, or "knocked out", an existing gene by replacing it or disrupting it with an artificial piece of DNA. They are important animal models for studying the role of genes which have been sequenced but whose functions have not been determined. By causing a specific gene to be inactive in the mouse, and observing any differences from normal behaviour or physiology, researchers can infer its probable function. Mice are currently the laboratory animal species most closely related to the humans for which the knockout technique can easily be applied. They are widely used in knockout experiments, especially those investigating genetic questions that relate to human physiology. Gene knockout in rats is much harder and has only been possible since 2003.[1][2] The first recorded knockout mouse was created by Mario R. Capecchi, Martin Evans, and Oliver Smithies in 1989, for which they were awarded the 2007 Nobel Prize in Physiology or Medicine. Aspects of the technology for generating knockout mice, and the mice themselves have been patented in many countries by private companies. UseKnocking out the activity of a gene provides information about what that gene normally does. Humans share many genes with mice. Consequently, observing the characteristics of knockout mice gives researchers information that can be used to better understand how a similar gene may cause or contribute to disease in humans. Examples of research in which knockout mice have been useful include studying and modeling different kinds of cancer, obesity, heart disease, diabetes, arthritis, substance abuse, anxiety, aging and Parkinson's disease. Knockout mice also offer a biological and scientific context in which drugs and other therapies can be developed and tested. Millions of knockout mice are used in experiments each year.[3] StrainsThere are several thousand different strains of knockout mice.[3] Many mouse models are named after the gene that has been inactivated. For example, the p53 knockout mouse is named after the p53 gene which codes for a protein that normally suppresses the growth of tumours by arresting cell division and/or inducing apoptosis. Humans born with mutations that deactivate the p53 gene suffer from Li-Fraumeni syndrome, a condition that dramatically increases the risk of developing bone cancers, breast cancer and blood cancers at an early age. Other mouse models are named according to their physical characteristics or behaviours. ProcedureThere are several variations to the procedure of producing knockout mice; the following is a typical example.
A detailed explanation of how knockout (KO) mice are created is located at the website of the Nobel Prize in Physiology or Medicine 2007.[4] LimitationsThe National Institutes of Health discusses some important limitations of this technique.[5]
There is variability in the whole procedure depending largely on the strain from which the stem cells have been derived. Generally cells derived from strain 129 are used. This specific strain is not suitable for many experiments (e.g., behavioural), so it is very common to backcross the offspring to other strains. Some genomic loci have been proven very difficult to knock out. Reasons might be the presence of repetitive sequences, extensive DNA methylation, or heterochromatin. The confounding presence of neighbouring 129 genes on the knockout segment of genetic material has been dubbed the "flanking-gene effect".[6] Methods and guidelines to deal with this problem have been proposed.[7][8] Another limitation is that conventional (i.e. non-conditional) knockout mice develop in the absence of the gene being investigated. At times, loss of activity during development may mask the role of the gene in the adult state, especially if the gene is involved in numerous processes spanning development. Conditional/inducible mutation approaches are then required that first allow the mouse to develop and mature normally prior to ablation of the gene of interest. Another serious limitation is a lack of evolutive adaptations in knockout model that might occur in wild type animals after they naturally mutate. For instance, erythrocyte-specific coexpression of GLUT1 with stomatin constitutes a compensatory mechanism in mammals that are unable to synthesize vitamin C.[9] See also
References1. ^{{cite journal | first = Helen R. | last = Pilcher | name-list-format = vanc | url = http://www.nature.com/news/1998/030512/full/news030512-17.html |title=It's a knockout |publisher=Nature |date=2003-05-19 |accessdate=2014-04-03 |doi=10.1038/news030512-17}} 2. ^{{cite journal | vauthors = Zan Y, Haag JD, Chen KS, Shepel LA, Wigington D, Wang YR, Hu R, Lopez-Guajardo CC, Brose HL, Porter KI, Leonard RA, Hitt AA, Schommer SL, Elegbede AF, Gould MN | title = Production of knockout rats using ENU mutagenesis and a yeast-based screening assay | journal = Nature Biotechnology | volume = 21 | issue = 6 | pages = 645–51 | date = June 2003 | pmid = 12754522 | doi = 10.1038/nbt830 }} 3. ^1 {{cite web | first = Geoff | last = Spencer | name-list-format = vanc | url = http://www.genome.gov/10005834 |title=Background on Mouse as a Model Organism | publisher = National Human Genome Research Institute | date = December 2002 | accessdate = 2014-04-03 }} 4. ^{{cite web|url=https://www.nobelprize.org/nobel_prizes/medicine/laureates/2007/advanced.html |title=The Nobel Prize in Physiology or Medicine 2007 |publisher=Nobelprize.org |date=1985-09-19 |accessdate=2014-04-03}} 5. ^{{cite web | url = http://www.genome.gov/12514551 | title = Knockout Mice Fact Sheet | publisher = National Human Genome Research Institute | date= August 2015 | accessdate = 2014-04-03 }} 6. ^{{cite journal | vauthors = Gerlai R | title = Gene-targeting studies of mammalian behavior: is it the mutation or the background genotype? | journal = Trends in Neurosciences | volume = 19 | issue = 5 | pages = 177–81 | date = May 1996 | pmid = 8723200 | doi = 10.1016/S0166-2236(96)20020-7 }} 7. ^{{cite journal | vauthors = Wolfer DP, Crusio WE, Lipp HP | title = Knockout mice: simple solutions to the problems of genetic background and flanking genes | journal = Trends in Neurosciences | volume = 25 | issue = 7 | pages = 336–40 | date = July 2002 | pmid = 12079755 | doi = 10.1016/S0166-2236(02)02192-6 | authorlink2 = Wim Crusio }} 8. ^{{cite journal | vauthors = Crusio WE, Goldowitz D, Holmes A, Wolfer D | title = Standards for the publication of mouse mutant studies | journal = Genes, Brain, and Behavior | volume = 8 | issue = 1 | pages = 1–4 | date = February 2009 | pmid = 18778401 | doi = 10.1111/j.1601-183X.2008.00438.x }} 9. ^{{cite journal | vauthors = Montel-Hagen A, Kinet S, Manel N, Mongellaz C, Prohaska R, Battini JL, Delaunay J, Sitbon M, Taylor N | title = Erythrocyte Glut1 triggers dehydroascorbic acid uptake in mammals unable to synthesize vitamin C | journal = Cell | volume = 132 | issue = 6 | pages = 1039–48 | date = March 2008 | pmid = 18358815 | doi = 10.1016/j.cell.2008.01.042 }} External links{{Library resources box|onlinebooks=no |by=no}}{{refbegin}}
3 : Genetically modified organisms|Laboratory mouse strains|1989 in biotechnology |
随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识,基本涵盖了大多数领域的百科知识,是一部内容自由、开放的电子版国际百科全书。