Rabies virus vector transgene expression level and cytotoxicity improvement induced by deletion of glycoprotein gene

• Published in: PloS one Vol. 8; no. 11; p. e80245
• Main Authors: Ohara, Shinya, Sato, Sho, Oyama, Kei, Tsutsui, Ken-Ichiro, Iijima, Toshio
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 07.11.2013; Public Library of Science (PLoS)
• Subjects: Action Potentials; Animals; Antigens, Viral - genetics; Apoptosis; Cell Line; Circuits; Cytotoxicity; Fluorescence; Gene Deletion; Gene Expression; Genes; Genetic Engineering; Genetic vectors; Genetic Vectors - chemistry; Genomes; Glycoproteins; Glycoproteins - deficiency; Glycoproteins - genetics; Health aspects; Humans; Infection; Infections; Life sciences; Luminescent Proteins - genetics; Luminescent Proteins - metabolism; Lyssavirus; Nervous system; Neural circuitry; Neural networks; Neurons; Neurons - pathology; Neurons - virology; Neurosciences; Proteins; Rabies; Rabies - virology; Rabies virus - genetics; Rabies virus - growth & development; Rabies virus - pathogenicity; Rats; Rats, Wistar; Receptors; Red Fluorescent Protein; Toxicity; Transgenes; University graduates; Vectors (Biology); Viral Envelope Proteins - deficiency; Viral Envelope Proteins - genetics; Virulence; Virus Replication; Viruses; Japan
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0080245

The glycoprotein (G) of rabies virus (RV) is required for binding to neuronal receptors and for viral entry. G-deleted RV vector is a powerful tool for investigating the organization and function of the neural circuits. It gives the investigator the ability to genetically target initial infection to particular neurons and to control trans-synaptic propagation. In this study we have quantitatively evaluated the effect of G gene deletion on the cytotoxicity and transgene expression level of the RV vector. We compared the characteristics of the propagation-competent RV vector (rHEP5.0-CVSG-mRFP) and the G-deleted RV vector (rHEP5.0-ΔG-mRFP), both of which are based on the attenuated HEP-Flury strain and express monomeric red fluorescent protein (mRFP) as a transgene. rHEP5.0-ΔG-mRFP showed lower cytotoxicity than rHEP5.0-CVSG-mRFP, and within 16 days of infection we found no change in the basic electrophysiological properties of neurons infected with the rHEP5.0-ΔG-mRFP. The mRFP expression level of rHEP5.0-ΔG-mRFP was much higher than that of rHEP5.0-CVSG-mRFP, and 3 days after infection the retrogradely infected neurons were clearly visualized by the expressed fluorescent protein without any staining. This may be due to the low cytotoxicity and/or the presumed change in the polymerase gene (L) expression level of the G-deleted RV vector. Although the mechanisms remains to be clarified, the results of this study indicate that deletion of the G gene greatly improves the usability of the RV vector for studying the organization and function of the neural circuits by decreasing the cytotoxicity and increasing the transgene expression level.