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Avian sarcoma leukosis virus receptor-envelope system for simultaneous dissection of multiple neural circuits in mammalian brain

Matsuyama, Makoto, Ohashi, Yohei, Tsubota, Tadashi, Yaguchi, Masae, Kato, Shigeki, Kobayashi, Kazuto, Miyashita, Yasushi
Proceedings of the National Academy of Sciences of the United States of America 2015 v.112 no.22 pp. E2947
Alpharetrovirus, brain, fluorescent labeling, genes, mammals, neural pathways, neurons, receptors
Pathway-specific gene delivery is requisite for understanding complex neuronal systems in which neurons that project to different target regions are locally intermingled. However, conventional genetic tools cannot achieve simultaneous, independent gene delivery into multiple target cells with high efficiency and low cross-reactivity. In this study, we systematically screened all receptor–envelope pairs resulting from the combination of four avian sarcoma leukosis virus (ASLV) envelopes (EnvA, EnvB, EnvC, and EnvE) and five engineered avian-derived receptors (TVA950, TVB S³, TVC, TVB ᵀ, and DR-46TVB) in vitro. Four of the 20 pairs exhibited both high infection rates (TVA–EnvA, 99.6%; TVB S³–EnvB, 97.7%; TVC–EnvC, 98.2%; and DR-46TVB–EnvE, 98.8%) and low cross-reactivity (<2.5%). Next, we tested these four receptor–envelope pairs in vivo in a pathway-specific gene-transfer method. Neurons projecting into a limited somatosensory area were labeled with each receptor by retrograde gene transfer. Three of the four pairs exhibited selective transduction into thalamocortical neurons expressing the paired receptor (>98%), with no observed cross-reaction. Finally, by expressing three receptor types in a single animal, we achieved pathway-specific, differential fluorescent labeling of three thalamic neuronal populations, each projecting into different somatosensory areas. Thus, we identified three orthogonal pairs from the list of ASLV subgroups and established a new vector system that provides a simultaneous, independent, and highly specific genetic tool for transferring genes into multiple target cells in vivo. Our approach is broadly applicable to pathway-specific labeling and functional analysis of diverse neuronal systems.