A rabies virus-based toolkit for efficient retrograde labeling and monosynaptic tracing.

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Understanding neural networks is key to brain function and disease research.
• Rabies viral vectors are valuable for tracing neural connections but face production challenges.
• Existing vectors have limitations in preparation time and yield for functional network studies.

Purpose of the Study:

• To develop an improved production system for rapid, high-titer rabies viral vectors.
• To create a versatile toolkit for structural and functional neural circuit analysis.
• To overcome limitations of existing viral vectors in neural tracing.

Main Methods:

• Developed a rapid rescue and high-titer production system for CVS-N2c-ΔG virus.
• Utilized N2cG-coated CVS-N2c-ΔG for retrograde labeling of projection neurons.
• Employed oG-mediated CVS-N2c-ΔG for trans-monosynaptic tracing.
• Assessed gene delivery for neural activity monitoring and transgene recombination.

Main Results:

• The new CVS-N2c-ΔG toolkit demonstrated efficient retrograde access to projection neurons, outperforming rAAV9-Retro.
• Trans-monosynaptic tracing efficiency was 2-3 times higher than with SAD-B19-ΔG.
• The system enabled gene delivery for neural activity monitoring with a 3-week maintenance window.
• Sufficient recombinase expression for efficient transgene recombination was achieved.

Conclusions:

• The novel CVS-N2c-ΔG-based toolkit offers a versatile solution for neural circuit research.
• This system significantly improves efficiency and speed in viral vector preparation and application.
• The toolkit facilitates advanced structural and functional studies of the brain's neural networks.