CRISPR Gene Editing That Turns Itself Off

This patent describes a CRISPR gene editing system that turns itself off after making a specific genetic change, using a second guide RNA to inactivate the editing enzyme.

What it covers

This patent describes a genome editing system that precisely modifies a target gene and then deactivates itself. It uses three main parts: a first 'guide RNA' (gRNA) that directs a CRISPR nuclease to the specific gene needing modification, the CRISPR nuclease itself which performs the editing, and a second gRNA. This second gRNA is designed to target a sequence within the CRISPR nuclease's own genetic code. Once introduced into a cell, the nuclease first makes the desired changes to the target gene. Then, the second gRNA guides the nuclease to its own coding sequence, causing an 'inactivating mutation' that effectively breaks the nuclease, preventing it from making further, potentially unwanted, edits. For example, a scientist could use this system to correct a single faulty base in a gene, and then the editing tool would self-destruct.

What it doesn't cover

• —Does not cover CRISPR systems that remain active indefinitely after making their intended genetic changes.
• —Does not cover gene editing systems that lack the specific 'second gRNA' designed to target and inactivate the CRISPR nuclease itself.
• —Does not cover systems where the inactivating mutation is not within the coding sequence of the CRISPR nuclease, as specified in claim 1.
• —Does not cover CRISPR nucleases that are not 'single-base editing' nucleases, as specified in claim 1.
• —Does not cover systems that do not use three separate expression constructs for the gRNAs and the CRISPR nuclease.

The clever bit

The clever part is using the CRISPR system's own mechanism to trigger its self-destruction. By designing a second guide RNA that targets the CRISPR nuclease's own genetic instructions, the system ensures that the editing tool is inactivated after it has completed its primary task, preventing prolonged activity.

Why it matters

CRISPR gene editing can sometimes make unintended changes (called off-target edits) or stay active for too long, which can be risky for therapies. This self-inactivating system helps solve these problems by ensuring the CRISPR tool only works for a short, controlled time. This increased precision and safety is crucial for developing gene therapies for human diseases and for making accurate genetic changes in agriculture.

Real-world examples

• 1.Gene therapy research for inherited diseases
• 2.Developing disease-resistant crops
• 3.Basic biological research in cell lines
• 4.Precision medicine applications