PRV-805 Grand Release! Independently Developed in China, Unlocking a New Chapter in Brain Science Research!

Time：2025-02-11 10:41:15

Pseudorabies virus (PRV) is widely used for tracing neural circuits across multiple synapses. By injecting PRV into peripheral sites such as the heart, gastrointestinal tract, and liver, researchers can trace brain nuclei that regulate these organs. Additionally, PRV can be directly injected into the central nervous system to map multisynaptic neural circuits.

However, traditional methods face limitations in accurately identifying input neurons, especially those expressing specific neurotransmitters, neuropeptides, or receptors, due to the virus infecting multiple neuron types.

To address this challenge, Brain Case introduces PRV-805 (PRV-△TK-DIO-mCherry), an innovative retrograde tracing virus. PRV-805 selectively replicates only in neurons expressing Cre recombinase and in neurons synaptically connected to the starter cells. By expressing red fluorescent protein, it precisely labels these neurons, enabling highly specific tracing of neuronal inputs.

Figure 1: Retrograde Labeling of PRV-805 in Vgat-Cre Mice

Internal test data show that after injecting PRV-805 into the hypothalamus of Vgat-Cre mice and performing perfusion two days later, fluorescence imaging revealed red fluorescent signals at the injection site as well as in brain regions such as the hippocampus, amygdala, medial septal nucleus, dorsal raphe nucleus, and bed nucleus of the stria terminalis (Figure 1).

In contrast, no fluorescence signal was detected in C57 mice, confirming that PRV-805 successfully achieved specific retrograde trans-synaptic tracing of starter neurons. This innovative technology enables more precise neural circuit analysis in neuroscience research, facilitating the exploration of complex brain functions.

1. Case Study

In 2001, the team led by Jeffrey M. Friedman at the Howard Hughes Medical Institute, University of California, published a research paper titled "Virus-Assisted Mapping of Neural Inputs to a Feeding Center in the Hypothalamus" in Science (IF = 44.7). The study developed a pseudorabies virus, PRV-Ba2001, capable of retrograde tracing of specific neurons. This virus encodes a green fluorescent protein marker and replicates only in neurons that express Cre recombinase and those synaptically connected to the starter cells.

A bicistronic construct was created in the PRV genome, where the CMV promoter was cloned upstream of a Tau-GFP fusion gene, followed by an internal ribosome entry site (IRES) at the 5' end of the endogenous thymidine kinase (TK) gene. A Lox-Stop-Lox (LSL) sequence was inserted between the CMV promoter and the start codon of the Tau-GFP open reading frame, with an SV40 polyA transcriptional terminator positioned between the two LoxP sites. In the absence of Cre recombinase, this terminator prevents the expression of downstream sequences. Therefore, the expression of TK and GFP is strictly dependent on Cre recombinase-mediated excision.

When the virus was injected into the arcuate nucleus of NPY-Cre mice (neuropeptide Y neuron-specific Cre mice), brain section imaging showed that these neurons received inputs from neurons located in the hypothalamus, amygdala, cortex, and other brain regions.

Figure 2: Structure and Expression Characteristics of PRV-Ba2001

On February 1, 2022, the team led by Sushil G. Rane at the National Institutes of Health (NIH) published a research paper titled "A distinct hypothalamus-to-b cell circuit modulates insulin secretion" in Cell Metabolism (IF = 27.7). In this study, they developed a new Cre-dependent PRV virus—PRV-Ba2017.

Compared to the previous generation of Cre-dependent retrograde tracers (Ba2001), Ba2017 demonstrated improved genetic stability and higher expression efficiency. The genetic coding sequence includes:CAG promoter, LoxP site, SV40 polyA transcription terminator, Lox2272 site, Inverted TK sequence, Inverted enhanced green fluorescent protein (EGFP) sequence, Inverted LoxP and Lox2272 sites, WPRE post-transcriptional regulatory sequence, BGH polyA transcription terminator.

To minimize leaky expression in the absence of Cre recombinase, the authors utilized the DIO/FLEX system, introducing two different pairs of Lox sites (LoxP and Lox2272).

When Ba2017 was injected into the pancreatic ducts of Ins1-Cre mice (pancreatic β-cell-specific Cre mice), green fluorescent signals were detected in the exocrine pancreas, spinal cord, brainstem, and paraventricular nucleus (PVN).

Figure 3: Infection of Pancreatic Islet β-Cells in Ins1-Cre Mice with PRV-Ba2017

2. Customer Feedback

(1) A customer successfully injected PRV-805 into the spinal cord of Cre transgenic mice, achieving clearly visible tracing results. This demonstrates the high-efficiency tracing capability of PRV-805 in the central nervous system (Figure 4).

Figure 4: Tracing Results of PRV-805 Injection in the Spinal Cord of Cre Transgenic Mice

(2) A customer injected PRV-805 into the tongue of Cre transgenic mice, and imaging results showed that PRV-805 exhibited excellent tracing performance in the peripheral nervous system, further validating its broad application potential (Figure 5).

Figure 5: Tracing Results of PRV-805 Injection in the Tongue of Cre Transgenic Mice

Summary

PRV-805 has shown excellent Cre-dependent retrograde trans-synaptic labeling results in spinal cord and tongue injections. However, there may be some limitations in joint cavity injections, and it is recommended to adjust the injection protocol according to specific experimental needs.

A small quantity of the same batch of products is still in stock based on customer feedback. We are offering 15 discount spots for a limited time, available on a first-come, first-served basis! For more details, please contact us at bd@ebraincase.com