The National Institutes of Health has awarded a grant of $1.2 million to the Mouse Biology Program at the University of California, Davis, to create mice that are susceptible to the COVID-19 virus, and to distribute them to researchers.

The goal is to create mice that can be used to reproduce human COVID-19 disease, said Kent Lloyd, director of the Mouse Biology Program and professor in the Department of Surgery at the UC Davis School of Medicine.

Mice and rats are not naturally infected by SARS-CoV-2, the virus that causes COVID-19. The virus enters human cells by attaching to a protein called ACE2. Lloyd’s team plans to create “humanized” laboratory mice by using CRISPR-Cas9 technology to precisely replace the genetic code for the mouse equivalent of ACE2 with the code for human ACE2.

They will also do the same with other human proteins thought to play a role in COVID-19 disease, such as TMPRSS2, which is thought to work with ACE2 to get the virus into cells. These lab mice will enable new investigations of how the virus attacks the body, why some people are more susceptible than others, and how COVID-19 might be prevented or treated.

As new genes involved in COVID-19 disease are discovered, they could also be engineered into mice, Lloyd said. Researchers might even be able to look at the effect of genetic variations in key genes on the course of disease.

Lloyd expects the mice to become available in about six months. The UC Davis Mouse Biology Program is a member of the NIH-funded Mutant Mouse Resource and Research Centers. The network collects and characterizes gene-modified and genetic knockout lab mice, and makes them available to researchers worldwide. The NIH recently renewed funding for the UC Davis center, now in its 21st year, for another five years.