University of California-Irvine neurobiologists have discovered a protein complex in neurons that is essential to long-term memory formation and is also corrupted in the brains of people with some developmental disabilities such as autism.
This complex is corrupted by the mutation of a specific protein molecule, and replacing that mutated molecule in laboratory mice restores their long-term memory — suggesting a possible gene therapy for humans, the researchers reported. Protein complexes access genes — portions of DNA — and turn them on and off at the right time to enable neurons in the brain to work properly, said Marcelo Wood, associate professor at UCI's Center for the Neurobiology of Learning and Memory and director of the Interdepartmental Neuroscience Program.
Wood's lab has identified nBAF as the protein complex needed for long-term memory. That protein complex is found only in neurons. When nBAF is corrupted by a mutation of its gene-encoding molecule baf53b, it can no longer perform the role of "nucleosome remodeling," the means by which nBAF accesses genes.
When UCI researchers replace mutated baf53b with non-mutated baf53b in lab mice, it leads to a functioning gene-accessing nBAF protein complex and results in the return of their long-term memory, Wood said.
This research furthers the science of epigenetics, which has to do with gene access and gene function without a change to DNA coding. Cognitive impairments in learning and memory and neurodevelopmental disorders once thought to be genetic may be epigenetic. The emerging field of epigenetics — changes to the expression of genes without any changes in their underlying DNA coding — suggests that the environment and the things we're exposed to can alter our gene function without changing our genetics. Epigenetics is why one twin, in a set of identical twins who share the same DNA, might get autism, cancer or another disorder, while the other one doesn't, Wood said.
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First engineered blood vessel is implanted
A 62-year-old Virginia man with kidney failure received the first genetically engineered blood vessel in the United States, a vein that may improve his dialysis treatments and pave the way for future tissue transplants.
The operation at Duke University Hospital in Durham, N.C., marked the first time doctors have implanted an "off-the-shelf" tissue graft in the United States. The vessel, grown with human cells on a mesh tube, has the potential to be widely used since it was cleansed of any lingering cells that may trigger an immune reaction, said the doctors who performed the surgery.
