Transgenic mice—genetically modified mice with added or deleted genes—are the unsung heroes of drug development. These tiny lab warriors help scientists understand diseases, test drugs, and even produce monoclonal antibodies used as medicines. If there’s a scientific breakthrough to be had, you can bet a transgenic mouse is somewhere in the mix!

Medical Marvel

But how do researchers turn an ordinary mouse into a biotech marvel? Let’s break it down. It all starts in the lab, where scientists tweak a mouse’s genetic code to create a model that mimics human diseases.

• Microinjection: Scientists inject foreign DNA into a fertilized mouse egg. The modified embryos are then implanted into a female mouse, which gives birth to transgenic offspring.
• Stem Cell Manipulation: Instead of injecting DNA directly, scientists introduce genetic changes in mouse stem cells, which are then inserted into an early-stage embryo. This method allows for targeted gene edits.
• CRISPR: The newest, most precise method. CRISPR works like molecular scissors, cutting and pasting DNA at specific spots. This allows for precise genetic changes.

Knock, Knock

Not all transgenic mice are created equal. Scientists tailor different models for different research needs.

• Knock-in mice have a foreign gene added to their genome. Scientists use them to study how specific genes function in diseases like cancer or Alzheimer’s.
• Knock-out mice have a specific gene deleted from their genome. This helps researchers understand what happens when a gene stops working. Hello, genetic diseases!
• Conditional knock-out mice are a high-tech version where genes can be turned on or off at specific times or in certain tissues.

Big Love

Big pharma relies on mice models at every stage of drug development:

• Early Disease Research: Scientists study how diseases develop at the genetic level.
• Drug Testing: New treatments are tested in mouse models before moving to human trials.
• Biologic Production: Some transgenic mice even produce human proteins, like monoclonal antibodies, for drug therapies.

Fame

Three famous mouse models include:

• OncoMouse® – Developed to have tumors for cancer research.
• APP/PS1 Mice – Engineered to model Alzheimer’s disease.
• HuCD34+ Mice – Used for immunotherapy and infectious disease research.

Price Tag

While exact figures are difficult to pinpoint, creating a high-end, transgenic mouse model can cost $1 million – $5 million to develop a new transgenic strain from scratch. Labs pay $10,000 – $100,000 per mouse for highly customized, commercially available models. Ongoing costs for maintenance, breeding, and licensing fees add even more to the bill. Would you pay $100K for a single mouse? If it helps cure cancer, maybe so.

The Bottom Line

Modern drug development would be slower, riskier, and way more expensive without transgenic mice. These tiny, genetically enhanced creatures are helping bring new treatments to patients faster than ever. Now, who’s ready to appreciate mice a little more?!