An intein-split transactivator for intersectional neural imaging and optogenetic manipulation

The cell-type-specific recording and manipulation is instrumental to disentangle causal neural mechanisms in physiology and behavior and increasingly requires intersectional control; however, current approaches are largely limited by the number of intersectional features, incompatibility of common effectors and insufficient gene expression. Here, we utilized the protein-splicing technique mediated by intervening sequences (intein) and devised an intein-based intersectional synthesis of transactivator (IBIST) to selectively control gene expression of common effectors in multiple-feature defined cell types in mice. We validated the specificity and sufficiency of IBIST to control fluorophores, optogenetic opsins and Ca²⁺ indicators in various intersectional conditions. The IBIST-based Ca²⁺ imaging showed that the IBIST can intersect five features and that hippocampal neurons tune differently to distinct emotional stimuli depending on the pattern of projection targets. Collectively, the IBIST multiplexes the capability to intersect cell-type features and controls common effectors to effectively regulate gene expression, monitor and manipulate neural activities.