Long-term precision editing of neural circuits in mammals using engineered gap junction hemichannels

Summary

The coordination of activity between brain cells is a key determinant of neural circuit function; nevertheless, approaches that selectively regulate communication between two distinct cellular components of a circuit, while leaving the activity of the presynaptic brain cell undisturbed remain sparse. To address this gap, we developed a novel class of electrical synapses by selectively engineering two connexin proteins found in Morone americana (white perch fish): connexin34.7 (Cx34.7) and connexin35 (Cx35). By iteratively exploiting protein mutagenesis, a novel in vitro assay of connexin docking, and computational modeling of connexin hemichannel interactions, we uncovered the pattern of structural motifs that broadly determine connexin hemichannel docking. We then utilized this knowledge to design Cx34.7 and Cx35 hemichannels that dock with each other, but not with themselves nor with other major connexins expressed in the mammalian central nervous system. We validated these hemichannels in vivo using C. elegans and mice, demonstrating that they can facilitate communication across neural circuits composed of pairs of genetically distinct cell types and modify behavior accordingly. Thus, we establish a potentially translational approach, ‘Long-term integration of Circuits using connexins’ (LinCx), for context-precise circuit-editing with unprecedented spatiotemporal specificity in mammals.