The magical animal- knock in mouse
Author: Sherlock
What is the knock in?
Gene knock in is a genetic engineering method, involving one to one substitution or inserting DNA sequence information into gene sequences. The knock in of the mutant allele in the mouse genome can be realized by homologous recombination in the embryonic stem cell (ES) cells, similar to the method used to produce conditional knock in mouse. However, instead of deleting part of the target gene, the specific mutation can be introduced into the endogenous gene and transmitted in the mouse reproductive system. The DNA constructs containing the target genes are incorporated into the ES cells through the same sequence flanks in the target loci, in which the homologous sequences are aligned and reorganized to transfer the altered genes into the endogenetic locus.
The following picture is the methods of the production of the knock in mice.
Why do people create the magical animal?
A key link in medical research and development is animal experiments. In order to study the treatment of cancer drugs, there must be a mouse model of cancer. In order to study diabetes, a diabetic mouse model is needed. After knocking out one or more genes of all of the thirty thousand genes in the mice, the mice were developed to become an animal model suitable for clinical trials of drugs and can be used to mimic human patients for research and treatment. These animals are a very important part of the biopharmaceutical industry chain.
How to produce the magical animals?
In general, there are two main ways to create the mice. First, gene knockin using gene homologous recombination. Gene knock in was developed in the second half of 80s using the principle of DNA homologous recombination. In the early 80s, the success of isolation and in vitro culture of embryonic stem cells (ES cells) laid the foundation for gene knock in. In 1985, the existence of homologous recombination in mammalian cells, which was first confirmed, laid the theoretical foundation for gene knock in. In 1987, Thompsson established a complete ES cell knock in mouse model for the first time. Until now, gene knock in using gene homologous recombination is still the most widely used method in constructing knock in animal models.
The following picture is the process of the knock in mouse:
The other one, the inducible gene knock in is based on the Cre/loxp system, but it can be induced by the activation of the promoter expressed by the Cre or the Cre enzyme activity expressed, by controlling the inducer for time or using the Cre gene to locate the host cell specificity of the carrier in the system and transfer the expression system. The technology of gene knock in to achieve the purpose of genetic modification to specific genes in the developmental stages of 1oxP animals and in certain tissue cells. It is possible to artificially control the spatio-temporal specificity of the animal gene mutation by the predesign of the inducers to give time to avoid the occurrence of stillbirth or soon after the birth of the animal. Several common inducible types are: tetracycline inducible; interferon inducible; hormone inducible; adenovirus mediated.
The end
As time going by, the research of knock in mouse will get more and more important. You can click here to get more information.
