How to Make a Transgenic Mouse

How to Make a Transgenic Mouse and What Technologies Can Be Used?

Understanding how to make a transgenic mouse is important for reasons that are relevant to the direction that genetic research has taken. Transgenic mice – primarily in the form of knockout mice – are an integral part of the research of diseases such as obesity, heart disease and Parkinson’s disease. They are also used for the purpose of understanding gene function and its effect on basic, physiological functions of the mammalian body.

A Quick Introduction to Transgenic Mice

Transgenic mice are genetically modified animals that involve the transfer of a type of genetic material known as a transgene, from one animal to the other. The idea behind creating transgenic mice is the possibility of using a DNA sequence that contains a gene isolated from the rest, and extracted for the purpose of being introduced into a different organism. This exchange is typically done from one mouse blastocyst to the other. In many cases, researchers opt to add a certain modification to the transgene, turning the resulting mouse model into a knockout mouse or an oncomouse. Learning how to make a transgenic mouse can take a lot of work, and the use of transgenes should be emphasized and understood before attempting anything more complex.

Transgene Use in Plants and Animals

The fact that transgenic specimens can be found naturally occurring throughout the natural world is no surprise. In fact, it has been something that scientists knew for many years. Naturally and genetically modified transgenic plants are being used on a regular basis to create GMO foods for the purpose of increasing crops. Some examples include corn, cotton, rice, rapeseed and soybeans. Also, learning how to make a transgenic mouse is not the only way to modify the genetic structure of an animal using a trasngene. Scientists have successfully devised methods of generating transgenic sheep and chicken models, and a great deal of research was focused on the transgenic alteration of Drosophila melanogaster (fruit fly) DNA.

A Short Overview of the Steps to Create Transgenic Mice

Before learning how to make a transgenic mouse, it is important to note that there are two distinct types of transgenic mice: knockout and oncomice. The process of generating them is similar, however, oncomice are known as transgenic models that use an oncogene for the purpose of studying cancer. To start the process of creating a transgenic knockout mouse, the first steps involve isolating stem cells from a male mouse and adding to it a mutated, inactive, “red” gene and a drug-resistant pink marker gene. As similar genes swap places, a process known as homologous recombination occurs. Since not all cells have incorporated the red gene, a drug is introduced, killing all cells that don’t contain the inactive version of the gene and the drug-resistant gene. The stem cells can then be transferred to a new mouse embryo, creating a chimera that will later become the first transgenic mouse model containing the inactive gene in question.

Important Recommendations for Preparing a Transgenic Mouse

Knowing how to make a transgenic mouse is not as easy as it sounds. All steps must be completed with the greatest of care and precision. Also, a focus on preparing clean samples of DNA will minimize the chance of an unhealthy embryo and inefficient DNA integration. Experts recommend the purified DNA to be dissolved in a microinjection buffer and centrifuged, to prevent the presence of impure particles.

Knockin vs. Transgenic Mouse Models

Since transgenic mouse models only include knockout mice, where do knockin mice come in? Knockin mice are different, in the respect that they involve a desired gene being introduced into a targeted locus through homologous recombination. In contrast, knockout transgenic mice are made through random integration, which makes them more suitable for the accurate study of genetic diseases. Learning how to make a transgenic mouse can, therefore, be a crucial research tool.