Improved Monosynaptic Neural Circuit Tracing Using Engineered Rabies Virus Glycoproteins

Area of Science:

• Neuroscience
• Molecular Biology
• Virology

Background:

• Monosynaptic rabies virus tracing identifies direct neuronal inputs.
• Current methods using SAD B19 strain glycoprotein (B19G) have limited efficiency.
• Improved transsynaptic spread is needed for comprehensive neural network analysis.

Purpose of the Study:

• To engineer novel glycoprotein variants for enhanced rabies virus transsynaptic efficiency.
• To evaluate the performance of these variants in tracing neuronal connections.
• To improve the identification of complete monosynaptic input neural networks.

Main Methods:

• Development of engineered glycoprotein variants, including oG (optimized glycoprotein).
• oG combines domains from B19G and rabies Pasteur virus glycoprotein.
• Testing oG's efficiency in rabies virus-mediated retrograde transsynaptic tracing.

Main Results:

• The engineered oG significantly enhances rabies virus tracing efficiency.
• oG increased tracing efficiency for long-distance inputs up to 20-fold compared to B19G.
• This advancement allows for the study of more complete neural input networks.

Conclusions:

• Engineered glycoprotein variants, particularly oG, substantially improve rabies virus tracing.
• oG facilitates more efficient and comprehensive identification of monosynaptic neural connections.
• This technology offers a powerful tool for mapping neural circuits.