Reengineering Life is a series from OneZero about the astonishing ways genetic technology is changing humanity and the world around us.
To study Covid-19 in the lab, scientists need animal models — that is, animals that mimic how a disease unfolds in humans. But there’s one big problem: Mice, the mainstay of laboratory research, are resistant to Covid-19 infection.
Scientists have been racing to find the best animal models to understand how the coronavirus infects cells and causes disease, as well as test experimental treatments and vaccines before the can be tried in humans. But since normal mice can’t be infected with the coronavirus, researchers have had to genetically engineer mice that can. Doing so involves adding a human gene to mice.
“Without genetically modifying a mouse, it’s not susceptible to [Covid-19] infection,” says Rob Taft, PhD, senior services program manager at the Jackson Laboratory, a nonprofit biomedical research institute in Bar Harbor, Maine. The lab is a leading supplier of research mice and has been overwhelmed with requests for them over the past few months.
The normal process for making these so-called transgenic mice is slow and inexact. These specially designed mice have also been in short supply since the pandemic began because so many scientists need them to study Covid-19.
But Chinese researchers recently created a mouse that can be used for Covid-19 research using a new method. They used a CRISPR-based process that seems to have some advantages over the traditional transgenic mice. They published their findings in the journal Cell Host & Microbe on May 26.
The Chinese team used the gene-editing tool CRISPR to engineer mice to contain the human gene for the ACE2 receptor, which is found on the surface of a wide range of human cells. This receptor is important to Covid-19 research because it’s the one that binds to SARS-CoV-2, allowing the virus to enter cells. The mouse version of ACE2 doesn’t allow the virus to enter cells. The resulting gene-edited mice ended up with the human receptor. When…