virus capsid-like protein used in the brain

The protein, Arc is similar in sequence to the viral ‘gag’ protein found in HIV1, but is found naturally in many species including at least humans and flies.

The Arc protein is not just similar in sequence to the viral gag protein, but also appears to have similar capabilities - it self-assembles into capsid-like structures, it binds RNA, and it . Both humans and flies require the Arc protein for both developmental and acute forms of synaptic plasticity.2

Curiously, the Arc protein is also involved in regulating the processes that chop up the beta-amyloid protein - the same protein that when aggregated seems to be responsible for Alzheimer’s Disease.3


Robust and reliable targeted delivery of genetic material is one of the outstanding challenges of existing gene therapies. One major issue with existing virus-based delivery of genetic material is that virus shells are seen by a person’s immune system as invaders, even when the harmful viral code has been removed. And as such, gene therapies can have immunogenic side effects and a patient can become ‘immune’ to therapeutic treatments. The Arc protein suggests a natural delivery tool for transferring genetic material between human cells that does not trigger an immune reaction. Because the Arc protein machine is already part of the human genome, and utilized extensively during neural development, it’s presence does not trigger an immune response.