Cat Lutz, senior director of the mouse repository and in vivo pharmacology at The Jackson Laboratory in Bar Harbor, in her lab. The laboratory has quickly bred, from its repository of stored genetic material, a colony of a mouse strain with the unique genetic makeup necessary for COVID-19 research. PHOTO COURTESY OF JACKSON LABORATORY

Saving mouse strains to protect future discoveries

BAR HARBOR — The Jackson Laboratory is playing a critical role not only in the urgent research into therapies or a vaccine for COVID-19, the disease caused by the SARS-CoV-2 virus, but also in preserving research material from other laboratories that have had to shut down their operations during the pandemic. 

In both of those efforts, the laboratory’s mouse repository is at the center of the action. 

“For decades, The Jackson Laboratory has helped scientists cryopreserve and recover embryos and sperm from important research mouse strains,” a recent video produced by the lab explains. “As a result, JAX has developed a repository of over 11,000 unique strains and we gain access to hundreds more each year from around the world.” 

The cryopreservation is “very much like you would see in a human IVF clinic,” said Cat Lutz, senior director of the mouse repository and in vivo pharmacology, in an article in Search, the lab’s magazine.

“Sperm and embryos are cryopreserved, and they’re able to be reanimated at any time. So, if a particular researcher is looking to have a mouse model for a particular disease that hasn’t been utilized in a long time, we can just reanimate that strain from the freezer.” 

That’s what happened with the current strain needed for research on the SARS-CoV-2 virus. In 2007, Paul McCray of the University of Iowa developed a mouse strain with the specific receptor that would allow the mouse to be infected with a human SARS-CoV strain. 

Now, 13 years later, the team at the mouse repository was able to quickly produce a colony of this strain of mice for use by researchers all over the world. 

The genetic engineering on that mouse strain is also ongoing, said Nadia Rosenthal, the lab’s scientific director, in a recent public lecture. 

“What we’re trying to do is getting closer and closer in the mouse to the kind of response that a human would experience if he or she got infected, so we can try out these treatments on the mouse,” she said. 

“What we now have is expertise in our Connecticut campus where scientists are actually taking the most important spike part out of the virus that causes COVID-19 and putting it into a harmless virus. That virus can actually get to a protein on the surface of the mouse cell, or the human cell, and that protein can sort of ferry that piece of spike into the cell.

“So, we can study the whole way this infection occurs without the danger of the full infection for humans because this is a completely disabled viral construct. It allows us to test a whole slew of different ways in which we can prevent that entry right in the cells in the dish in the lab.” 

And that, she said, “could be used to find ways to either vaccinate or to render humans much less susceptible to this virus. 

Research happening at The Jackson Laboratory has been able to continue, but elsewhere some research labs have had to suspend their activities. 

Organizations using animals are required to have plans to ensure the humane treatment of animals and continuity of research in an emergency, Rob Taft, a program manager at the lab’s mouse repository, said in Search magazine. “However, the current situation is creating concern that novel mouse strains that may hold the key to new treatments for disease could be lost to science,” he said. 

So, in addition to taking the one mouse strain from the University of Iowa out of the repository and creating a new colony, the team is also saving strains from other labs. They’re sending cryopreservation kits to labs around the world so researchers can freeze mouse sperm quickly and send it to the repository here. 

Keeping humans healthy 

Work is very much continuing at the lab’s Bar Harbor facility, with modifications including a requirement to wear cloth masks in common areas, an increase in shift work, and testing offered to employees working on site with symptoms of the disease. 

“We, as The Jackson Laboratory, don’t do highly infectious research, for obvious reasons,” Rosenthal noted. “We have two million little furry mice; we don’t want them to get sick.” 

All those years of experience in keeping mice healthy makes the transition to the new precautions a bit easier for the humans who work there, too. 

For people at home and in other workplaces, that expertise is summed up in familiar advice: hand washing, not touching your face, and avoiding close physical contact with anyone outside of your household, said Dr. Jens Rueter, medical director of the laboratory’s Maine Cancer Genomics Initiative. 

An extra cautionary measure is to wash all produce and fruit after purchasing it in the grocery store. This is best done right after entering your home,” he said. 

While there is no perfect way of avoiding the transmission of viruses and bacteria, these small modifications prove to be very effective in preventing further transmission.” 


Liz Graves

Liz Graves

Reporter at Mount Desert Islander
Former Islander reporter and editor Liz Graves grew up in California and came to Maine as a schooner sailor.

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