RNA-Guided Gene-Editing System Expands CRISPR Capability

Two complementary studies from Purdue University and Columbia University, published in Nature, describe a naturally evolved gene-editing system that activates genes rather than cutting DNA. The research reveals both the biological function and molecular mechanism of this CRISPR variant, which broadens understanding of CRISPR’s natural diversity and suggests new strategies for precise gene regulation.

Traditional CRISPR systems rely on molecular cutting to disable or edit genes. In contrast, this newly identified CRISPR mechanism turns genes on by guiding the cell’s own gene expression machinery to specific DNA sites. Because it operates without breaking DNA strands, it could be applied in research and potential therapeutic contexts that require temporary or controlled activation of genes rather than permanent genomic changes.

One study describes how the system uses a strand of RNA as a guide to locate exact DNA sequences and attract the elements responsible for transcribing DNA into RNA. The second study details how the structure of the molecular complex enables this process, showing that it recruits RNA polymerase—the enzyme that carries out transcription—to initiate gene activity. Together, these insights provide a comprehensive view of how this RNA-guided complex can stimulate gene expression.

The Purdue team used cryo-electron microscopy and biochemical experiments to clarify the structural and functional aspects of this system. The cryo-electron microscopy offered near-atomic resolution images of the complex, showing how the RNA guide directs it to its DNA target and aligns it to engage the transcription machinery. Laboratory experiments then confirmed that this interaction activates gene expression.

“In traditional CRISPR, RNA guides the complex to a DNA target to cut it. Here, the RNA still directs the complex to the target, but instead of cutting the DNA, it recruits the cell’s transcription machinery to activate gene expression,” said co-author Leifu Chang. “It’s like switching from molecular scissors to a GPS-guided activation switch.”

The studies further show that gene activation can occur even in genomic regions that lack promoter sequences typically required for transcription, indicating a natural expansion of CRISPR’s roles in living organisms.

“Our goal is to understand the fundamental mechanisms of RNA-guided molecular machines,” Chang said. “By defining how these systems work at a molecular level, we can lay the groundwork for safer and more versatile genome engineering technologies.”