AAV with CMV promoter driven Cre Inducible C1V1(E122T/E162T))-TS-Venus

This AAV expresses DIO-C1V1(E122T/E162T))-TS-Venus driven by an ubiquitous CMV promoter.

This roughly 0.6 Kb promoter is the commonly used human cytomegalovirus (CMV) immediate-early promoter/enhancer (CMV/IE).

C1V1 is a chimeric channelrhodopsin made to boost membrane expression higher than VChR1 but with a different light spectrum. It is composed of ChR1 and VChR1 fragments, and implements fast, potent optical excitation at red-shifted wavelengths. C1V1(E122T/162T) is highly efficient in neurons, with a maximum absorption at 530nM with a narrow action spectra. Off-kinetics is 35ms.

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.

In the DIO scenario, the transgene of interest is inserted in reverse orientation relative to the 5′ promoter and is flanked by oppositely oriented loxP and lox2272 sites. In the absence of Cre expression, the transgene will not be produced. In the presence of Cre expression, the transgene will be “FLip-EXchanged” or FLEXed, leading to expression of the transgene. This is due to a permanent Cre-mediated recombination/inversion of the flanked transgene. This arrangement is called DIO (double-floxed inverse ORF), Cre-ON, Flex-rev (reverse), Flex-ON/FlexON, or DIO-AAV/AAV-DIO (double-floxed inverse ORF in AAV).