The transgene contains the promoter region of the mouse actin, alpha 2, smooth muscle, aorta (Acta2) gene, including 1074 bp of 5' flanking region, the transcription start site, the 48-bp first exon, the ~2.5-kb first intron, and 15 bp of exon 2, driving expression of green fluorescent protein. Transgenic mice express GFP specifically in both vascular and nonvascular smooth muscle cells. (J:43053, J:191415)