A 2A-lexA::GAD cassette followed by a Disc\RFP3xP3.cUa marker has been inserted into the endogenous Octβ2R locus, at the 3' end of the open reading frame of the RA, RC, RD and RE isoforms. This results in the lexA::GAD driver being expressed as a separate protein under the control of endogenous Octβ2R regulatory sequences that control expression of these isoforms.