Igs7^{tm229(tetO-GCaMP6m,-ChRmine*,SYN1-tTA2)Tasic}

The targeting vector has a Tet response element (tetO), loxP-STOP-loxP cassette, GCaMP6m-IRES2-ChRmine-TS-Kv2.1-HA-WPRE, a CAG promoter, Lox2272-STOP-Lox2272 cassette, ChRmine* sequence, and then a fragment of the human synapsin 1 (SYN1) gene promoter, LoxN-STOP-LoxN cassette, and tTA2-WPRE sequence- all inserted into the T1 TIGRE locus (an intergenic region on chromosome 9 [between AB124611 and Carm1] determined to have low basal transcriptional activity and allow high Cre and/or Tet inducibility). ChRmine is a pump-like cation-conducting channelrhodopsin, derived from Rhodomonas lens, that exhibits extremely high current and light sensitivity, as well as a markedly red-shifted spectrum. GCaMP7m is an ultrasensitive EGFP fluorescent calcium detector of neuronal activity with medium decay and response kinetics. Of note, the Ai229 allele was designed with an IRES upstream of the ChRmine* sequence to reduce/eliminate leakiness in the absence of Cre recombinase. (J:101977)