Transgenic animal models

products-servicesPolyGene AG
July 6th 2015

About Transgenic Animals

Transgenic mice and other animals form the central pillars of mammalian genetics. A transgenic animal is one that carries a foreign gene that has been deliberately inserted into its genome. This is achieved using genetic recombination in which the DNA will also include other genetic sequences that allow the foreign gene to be expressed correctly by the host animal’s cells.

PolyGene’s innovative recombinant gene therapy methods allow for the production of animals carrying foreign genes in a predefined manner: as tissue-specific genes, as single-copy or multi-copy cluster, as fusion genes, or in inducible or repressible form.

They also allow for faster backcross breeding of congenic mice that differ from recipient strain at only one locus and linked segment of chromosome.

PolyGene offers services for developmental regulation of gene expression in comprehensive projects, as well as milestone steps for partial services, such as microinjection services, or vector construction.

Pronuclear microinjection service

With microinjection one or more designed genes or bacterial artificial chromosomes (BACs) can be inserted directly into the pronucleus of the oocyte to integrate randomly into the genome.

The main advantage of microinjection is that it allows transgenic mouse models to be developed in much shorter times. The complete development of a transgenic mouse line takes about two months. Level and pattern of the transgene expression can vary due to unknown copy number and integration site, which makes it necessary to analyze several independent transgenic lines.

PolyGene offers microinjection services for a variety of mouse and rat strains, including:

  • C57BL/6 mice
  • FVB mice
  • CB6F2 mice
  • Sprague rats

PolyGene can offer a wide range of other transgenic animal models, including rabbit models. Each model is guaranteed for number of offspring and founders.

Knockout and knockdown models

PolyGene is also experienced in working with knockout and gene knockdown models in transgenic mice.

Knockout transgenic mice

PolyGene can supply transgenic mice in which an existing gene is knocked out by replacing it with an artificial piece of DNA. These knockout mice are important transgenic models for studying the role of sequenced genes whose functions are yet to be determined. Researchers can use reverse genetics to infer probable function by causing the specific gene to be inactive in the mouse and observing any differences from normal behavior or physiology.

Mice are currently the most closely related laboratory animal species to 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. Some gene knockout in rats has become possible since 2003.

Knockdown models

Similar reverse genetics studies to identify specific sequenced gene function can be carried out using the knockdown mouse, in which expression of one or more of the animal’s genes is reduced (‘knocked down’) by treatment with a reagent such as an RNA oligonucleotide with a sequence complementary to gene or messenger RNA (mRNA). The end result is a knockdown organism in which specific gene expression is reduced or eliminated.

PolyGene can produce gene knockdown mice using mRNA, small interfering RNA (siRNA) or transcription activator-like effector nucleases (TALENs) in gene targeting.

Congenic mouse models

An animal model is congenic when it exhibits differential gene expression from a particular inbred strain at a single locus as a result of backcrossing a particular allele into the inbred strain.

Congenic strains are used to investigate the biological properties of the single different locus without the complications that arise from differences at other loci. For example, C57BL/10 Harlan mice are identical with DBA/2 mice over more than 99 per cent of their genome, crucially differing mainly at the H-2 locus. Differences in biological responses to infection, etc., can be studied by focusing on the H-2 complex.

Transgenic animal health

All transgenic mice and transgenic rats are held exclusively in Tecniplast IVC cages at PolyGene’s small mouse facility. The facility is rigorously managed to the highest standards, with continuous focus on enriching the life conditions of the animals under its care.

Donor colonies are replenished with Harlan, Charles River and Janvier SPF mice with SOPF mice also held in the post-transfer zone.

The animal facility is frequently and rigorously tested for Noro, Helicobacter and a number of further non-FELASA germs. Transgenic animals’ hygiene status is regularly checked according to the recommendations of the FELASA consortium, with repeated remating techniques uses to ensure maximal sensitivity.

PolyGene warrants hygiene for absence of Polyoma virus, Encephalitozoon cuniculi and all Pasteurellaceae, including Actinobacillus muris and Hantaan.

Resources

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Supplier Information
Supplier: PolyGene AG
Address: Riedmattstraße 9 CH – 8153 Rümlang, Switzerland
Tel: +41 44 – 818 88 00
Fax: +41 44 – 818 88 01
Website: http://www.polygene.ch/