Expanding the Repertoire of Optogenetically Targeted Cells with an Enhanced Gene Expression System

SummaryOptogenetics has been enthusiastically pursued in recent neuroscience research, and the causal relationship between neural activity and behavior is becoming ever more accessible. Here, we established knockin-mediated enhanced gene expression by improved tetracycline-controlled gene induction (KENGE-tet) and succeeded in generating transgenic mice expressing a highly light-sensitive channelrhodopsin-2 mutant at levels sufficient to drive the activities of multiple cell types. This method requires two lines of mice: one that controls the pattern of expression and another that determines the protein to be produced. The generation of new lines of either type readily expands the repertoire to choose from. In addition to neurons, we were able to manipulate the activity of nonexcitable glial cells in vivo. This shows that our system is applicable not only to neuroscience but also to any biomedical study that requires understanding of how the activity of a selected population of cells propagates through the intricate organic systems.

Graphical AbstractFigure optionsDownload as PowerPoint slideHighlights
► Stable, selective, high-level transgenic channelrhodopsin-2 (ChR2) expression was achieved
► Knocking in tetO-ChR2 into the β-actin gene locus was key to high expression
► Using a bigenic approach, seven distinctly expressing lines were obtained
► Formerly nonexcitable cells could also be activated by noninvasive light stimuli