AAV with CamKII(0.4) promoter driven eNpHR3.0-TdTomato

This AAV expresses eNpHR3.0-TdTomato driven by a neuron CamKII(0.4) promoter.

This 0.4 Kb promoter is derived from murine α-Calcium/calmodulin-dependent kinase II (CaMKII), a gene with expression restricted to excitatory neurons in the neocortex and hippocampus. It was shown that the promoter activity of CaMKII(0.4) is almost identical to that of CaMKII(1.3) in cortical neurons, Compared to CaMKII(1.3), this short promoter allows cloning of longer gene of interest into the AAV construct .

NpHR is a halorhodopsin or a light-sensitive chloride channel that provides silencing of neuronal activity by hyperpolarization. It offers fast inhibition, and its peak activation falls at 589 nm.

The trafficking signal (KSRITSEGEYIPLDQIDINV) is also from the inward rectifier potassium channel Kir2.1; it serves to dramatically reduce intracellular accumulation and improve membrane targeting, leading to a profound increase of photocurrents. This is the basis for many third-generation optogenetics tools.

This ER export motif (FCYENEV) is from the vertebrate inward rectifier potassium channel Kir2.1. The motif prevents aggregate formation, decreases intracellular accumulations, and enhances tolerability at high expression levels. This is the strategy for developing many second-generation optogenetics tools.