Enhancer viruses for combinatorial cell-subclass-specific labeling.

Area of Science:

• Neuroscience
• Genomics
• Molecular Biology

Background:

• Single-cell genomic analysis rapidly identifies diverse cell types.
• Efficient experimental access to identified cell types is limited.
• Targeting specific neural populations in the brain is crucial for research.

Purpose of the Study:

• To develop methods for experimental access to specific neural populations.
• To create tools for precise cell-type targeting in the mouse cortex.
• To enable detailed investigation of neuronal subclasses.

Main Methods:

• Collected single-cell chromatin accessibility data from mouse cortex.
• Identified cell-type-specific enhancers.
• Cloned enhancers into recombinant adeno-associated viruses (AAVs) for targeted gene delivery.
• Utilized a new transgenic mouse line (Ai213) with recombinase-expressing enhancer viruses.

Main Results:

• Enhancer-driven AAVs successfully drove transgene expression in specific cortical cell subclasses.
• Characterized AAVs labeled distinct projection neuron subclasses in mice.
• Demonstrated homologous neuron subclass labeling in human cortical slices.
• Combined enhancer viruses and Ai213 mice enabled robust labeling of multiple neuronal classes/subclasses in a single animal.

Conclusions:

• Developed a flexible and specific method for targeting neural populations using enhancer-driven AAVs.
• This approach facilitates the investigation of cell types in the mouse brain and has potential for broader applications.
• Enables precise genetic access to neuronal subclasses for future functional studies.