A federal judge upheld a ban on federal funding for embryonic stem cell research on Tuesday, halting many research projects in their tracks and affecting scientists nationwide.

The injunction was issued on Aug. 23 in response to a lawsuit involving two scientists who claimed their work with stem cells would be in danger of losing funding if embryonic stem cell research competed for federal money, according to court documents.

While the government looks to appeal the injunction in court, embryonic stem cell researchers at the National Institutes of Health have stopped their research and cannot continue unless the appeal comes through.

Labs outside the institute, including those at UCLA, are not allowed to apply for or renew federal grants for embryonic stem cell research, according to the injunction.

“(The US) won’t be able to participate in embryonic stem cell (research) and the rest of the world will go on without (the US),” said Gay Crooks, a professor in pathology and laboratory medicine and pediatrics and member of the Broad Center of Regenerative Medicine and Stem Cell Research at UCLA.

The National Institutes of Health is one of the largest federal sources of funding for embryonic stem cell research, appropriating $126 million for such research in 2011, according to the institute’s website.

Money from the institute goes to research, lab employees, lab facilities and infrastructure, Crooks said.

“If you take (the institute) away, it’s very hard to fill in that gap,” said Jerome Zack, a professor in the David Geffen School of Medicine who has two federal grants to study how embryonic stem cells can boost the human immune system.

Receiving a grant from the institute is a difficult task, Zack said. Funding is only granted to projects which pass a rigorous peer review, and that encompasses less than 10 percent of grant applicants.

Neither of Zack’s grants can be renewed under the court injunction, he said.

“The enormous amount of money that has been spent on (this type of research) has been halted,” Crooks said. “It’s a tremendous loss of time in terms of trying to find cures.”

Private funding sources, such as pharmaceutical companies and philanthropic organizations, are not large enough to match the kinds of grants the institute can give, Crooks said.

Post-doctoral scholars and young faculty who are looking for tenure at UCLA may not be able to apply for such grants if the injunction is not lifted, Zack said.

The injunction also affects research collaborations in which multiple labs are funded by a single federal grant, said Steven Peckman, associate director of the Broad Center.

“You see a tremendous ripple effect occurring,” he said.