The rtTA2S-M2 variant is expressed under the control of the hnRNPA2/B1 promoter. An ~8 kb DNA fragment was used that encompasses the human hnRNPA2/B1-CBX3 gene locus CpG island, which includes two divergently transcribed promoters. Seven transgenic lines were established through transmission of the transgene. Transgenic founder 2 had two integration sites, which separated upon breeding to generate lines 2a and 2b. Line 9 is the highest expressing line in all tissues tested, lines 2a and 2b expressed weakly in some tissues, whereas lines 1, 4, 6 and 7 expressed low but detectable levels. Line 9 was expanded and studied further.