Manipulating gene expression in projection-specific neuronal populations using combinatorial viral approaches.

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• The mammalian brain's complexity is crucial for its function.
• Advancements in gene expression profiling, connectivity mapping, and viral vector technology enable detailed study of gene-circuit interactions.

Purpose of the Study:

• To detail a protocol for combinatorial viral injections to manipulate gene expression in specific neuronal subsets.
• To enable the genetic dissection of neural circuitry by targeting interconnecting neurons.

Main Methods:

• Stereotaxic injection of CAV2-Cre virus (retrograde) into one brain region.
• Injection of a Cre-dependent adeno-associated virus (AAV) (local transduction) into a second brain region.
• Combinatorial use of viral vectors for target-selective gene manipulation.

Main Results:

• Selective manipulation of gene expression in neuronal subsets based on projection targets.
• Enables expression of various genetic tools (e.g., genes, dominant-negatives, reporters) in defined neuronal populations.

Conclusions:

• This technique provides a versatile method for genetically dissecting neural circuitry.
• Applicable to understanding gene function in specific neuronal connections within the brain.