A transgenic construct containing the entire open reading frame of the Cyan Fluorescent Protein (CFP) gene fused in-frame with the mitochondrial targeting sequence of the human cytochrome c oxidase subunit 8A (ubiquitous) gene under the direction of regulatory elements derived from the mouse Thy1 gene was injected into fertilized donor mouse eggs. Regulatory elements are composed of a 6.5 kb fragment obtained from the 5' portion of the Thy1 gene, extending from the promoter to the intron following exon 4. Exon 3 and its flanking introns are absent. The deleted sequences are required for expression in non-neural cells but not in neurons. The remainder of the sequence is required for neuronal expression. Founder line S2, corresponding to the published line S, was subsequently established. (J:122259)