knockout mouse

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a small rodent, various species of which are used in laboratory experiments.
1. a small loose body.
2. a computer pointing device.
joint mouse a movable fragment of synovial membrane, cartilage, or other body within a joint; usually associated with degenerative osteoarthritis and osteochondritis dissecans.
knockout mouse a mouse that has had a specific gene artificially deleted from its genome.
nude mouse a mouse homozygous for the nu gene; these mice are hairless, lack a thymus, and thus lack T lymphocytes.
peritoneal mouse a free body in the peritoneal cavity, probably a small detached mass or omentum, sometimes visible radiographically.
SCID mouse (severe combined immunodeficiency) a strain of mice lacking in T and B lymphocytes and immunoglobulins, either from inbreeding with an autosomal recessive trait or from genetic engineering, used as a model for studies of the immune system.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

knockout mouse

a mouse from whose genome a single gene has been artificially deleted.

Experimental animals lacking specific genes have become valuable research tools in many branches of medicine, including genetics, physiology, pharmacology, immunology, cell biology, and oncology. A transgenic animal is one into whose genome a foreign gene, constructed by recombinant DNA technology, has been deliberately inserted. Placement of the inserted gene at a specific locus in the genome is made possible by incorporating it in a vector in which it is flanked by DNA sequences unique to the target site. The artificial genetic material is introduced into an embryo, which then develops into a chimera whose tissues contain both normal cells and cells containing the transgene. Matings among such animals yield some offspring that are homozygous for the transgene. If the inserted gene is a nonfunctional (null) allele, it deletes or "knocks out" the normal, wild allele. Not only is the deleted gene not expressed, but the offspring of matings among homozygous individuals constitute a pure strain, all of whose members lack the gene. Although theoretically any animal could be subjected to the knockout technique, mice have been used almost exclusively. Mice are small and easily maintained and they reproduce rapidly and have a short life span. In addition, mouse and human genomes are strikingly similar, with about 75% correspondence of genes. That knockout mice lacking a wide variety of genes are often phenotypically normal indicates that the mouse genome, like that of human beings, often has sufficient redundancy to compensate for a single missing pair of alleles. Knockout mice lacking the p53 tumor suppressor gene are used in studies of carcinogenesis, and those lacking the gene for the low-density lipoprotein (LDL) receptor constitute an animal model of human familial hypercholesterolemia. Knockout mice have proved valuable in revealing the functions of genes for which mutant strains were not previously available.

Farlex Partner Medical Dictionary © Farlex 2012
A genetically engineered mouse created by gene targeting—targeted gene disruption—in which a specific gene is deleted or inactivated by homologous recombination, to study the effects of its absence. Knockout mouse models of human disease have been created for atherosclerosis, cancer, cystic fibrosis, etc.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

knock·out mouse

(nok'owt mows)
A mouse from whose genome a single gene has been artificially deleted.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
References in periodicals archive ?
The ASGCT presentation also highlights previously reported preclinical efficacy data of RP-A501 in LAMP-2 knockout mice which showed dose-dependent improvements and restoration of cardiac function, with responses observed in both older and younger KO mice.
'P4h-tm' knockout mice showed striking courage and a lack of learned helplessness compared to congenic wild-type mice with a functional 'P4h-tm' gene.
The Ragnase-1 knockout mice also showed physiological abnormalities like weight loss and an enlarged spleen, and they died at a young age.
New York, NY, November 27, 2018 --( A research group led by Hong Xue at Hong Kong University of Science and Technology, unveiled resources & recommendations that propose a new approach for investigator qualification - "analyzing the gene dosage impacts of GABAA receptor ?2 subunit gene (Gabrb2) in knockout mice of both heterozygous (HT) and homozygous (KO) genotypes concerning possible schizophrenia-like and comorbid phenotypes with microglia-dysregulation - a medical study that goes beyond repetitive training and includes individual experience and protocol-particulate preparation.
Mansukhani, M.D., from the Northwestern University Feinberg School of Medicine in Chicago, and colleagues fed low density lipoprotein receptor knockout mice a high-fat diet for 14 weeks, and then administered bi-weekly injections of the nanofibers or control for eight weeks.
Western blot analysis of total cell lysates from the kidney confirmed the absence of DNase1 in the knockout mice. We used an in vitro DNase activity assay on the basis of the measurement of DNA degradation activity, as previously described (5) with minor modifications.
In nonmodel group mice, TRPV1 expression was unchanged in Pirt knockout mice [15].
Vascular Specific Epac1 Knockout Mice. All animal procedures met the Association for Research in Vision and Ophthalmology requirements and were approved by the Institutional Animal Care and Use Committee of Wayne State University and conformed to NIH guidelines.
In the present study, we investigated memory impairment and neuronal cell death in A[[beta].sub.25-35]-injected Ftmt knockout mice. In addition, we explored the molecular mechanisms responsible for neuronal damage in this model.
Therefore, the aim of this study was to examine the changes of systemic responses to endotoxemia in SPAK knockout mice. Materials and Methods: Wild-type and SPAK knockout mice were randomly given with vehicle (saline) or Escherichia coli lipopolysaccharide (LPS, 50 mg/kg) and monitored for 24 h.
To test this model, we utilized knockout mice and enumerated hematopoietic bone marrow cells from femur washes by manual cell counting on a hemocytometer visualized by light microscopy.