Stanford Medicine researchers develop ultracompact TIGRa gene activation tool

Scientists at Stanford Medicine have developed an ultracompact gene activation tool named TIGRa (pronounced ‘tiger A’) that addresses a major limitation in current gene therapies. Traditional molecular tools, such as CRISPR-based systems, are often too bulky to be efficiently packaged into single viral vectors for delivery into human cells.

TIGRa functions as a molecular switch that does not rewrite DNA sequences but instead recruits a cell’s transcriptional machinery to increase the expression of existing genes. Because it is less than half the size of comparable CRISPR activators, it can be transported within a single adeno-associated virus.

In mouse models, researchers used TIGRa to activate two protective genes in retinal ganglion cells. The treatment allowed mice to retain partial vision following injuries that would otherwise lead to near-blindness, demonstrating potential for treating glaucoma and other retinal degenerative conditions.